The Salomon X Ultra 3 have a synthetic mesh upper with a Gore-Tex liner. The sole is Salomon's proprietary ContaGrip rubber, and there's an injected EVA midsole. A note on fit — we've tested Salomon shoes before and know that their US sizing is a little off for us (Salomon uses Euro sizing first and then converts it, but that conversion doesn't always line up with our standard US size). If you don't know your size in Salomon shoes it may take a bit of trial and error to dial in the right one for you — so make sure you order from somewhere with a good return policy.
Also, note that this pair is cut on the narrow side. They fit us well, but if you have wider feet you may want to consider some other models that either run wide or are offered in a wide model.
Performance Comparison

Looking for something that is light enough for fast hiking and running? This X Ultra 3 are the ones!
Photo: Cam McKenzie Ring
Comfort
We gave the X Ultra 3 a middle score for comfort. This pair is never uncomfortable in any significant way, but it didn't stand out for being super plush nor does it have a ton of cushioning.
This shoe has more cushioning in the heel than the forefoot, though Salomon did put some cushioning under the toes. It is not as plush as some of the models we tested, but it does have adequate cushioning for hikes without a heavy pack. Unlike most synthetic shoes, which feel comfortable right away, this pair did have a bit of a break-in period, and the upper is stiff at first. Once it softens up, it is more comfortable, as long as the laces don't bother you.

Once we broke this pair in a little the stiff synthetic upper softened up and they were comfortable enough for scenic hikes in beautiful places, like Bryce Canyon National Park.
Photo: Cam McKenzie Ring
The Quicklace system that is Salomon's trademark is not for everyone. It can be difficult to fine-tune the laces — all of them tighten at once, so if you want one section looser than the other, that's not really possible. There's also the issue of the dangling laces. Salomon gives you a lot of extra lacing material, and once we tightened the shoe, there was a long loop dangling down.

The Quicklaces are so long we could step on them! What to do? The pocket at the top of the tongue is obscured by the cinching tab, and when we tucked the end under the laces it created a pressure spot.
Photo: Cam McKenzie Ring
There is a pocket at the top of the tongue in which to store the end of the loop and cut down on the laces flopping around (it took us several weeks before we even noticed it was there!) but the laces cover that pocket, and it was challenging to use it. We tried tucking the ends under the other laces, but that created a pressure spot. It didn't annoy us quite enough to cut the Quicklaces out and replace them with standard laces, nor is that an option, as the holes in the lacing eyelets are small and wouldn't accommodate a standard pair of laces.

The pocket at the top of the tongue gets covered by the laces when you cinch them down. It was weeks before we even noticed that it was there!
Photo: Cam McKenzie Ring
Support
We got a lot of support from this shoe and gave it a better than average score for this category.
The X Ultra 3 has excellent torsional stability, and there is good arch support built into the shoe. The insole has some nice padding to it, though it's not structurally molded. The cut is on the narrow side, so if you were planning on putting an aftermarket insole in this shoe, you might want to consider sizing up a bit.

The Ortholit insole (right) that is included in this pair has some good cushioning to it, but not a lot of structure like the Oboz Sawtooth' (left).
Photo: Cam McKenzie Ring
Traction
We like the traction in this pair and gave it a high score for this category. The lugs are large, deep, and well-spaced, giving you good traction on loose, muddy and slippery trails. This sole is one of the most "aggressive" in our test group, and it works well, particularly when moving fast on the trail. The sole is made with Salomon's "ContaGrip" rubber. They chose to make their own sole, as opposed to partnering with Vibram like many other companies, and they made it well.
The only time we didn't have the best confidence in this shoe was when scrambling on bare rock. Because the upper and the sole is on the stiff side, you do have to exert a lot of pressure to get it to bend and get good smearing traction. That's where a slightly softer shoe has an advantage over the X Ultra 3.

We liked the traction that we got on dirt trails, but found them a little more challenging to use on steep rock because of the stiffer sole.
Photo: Cam McKenzie Ring
Weight
The X Ultra 3, while not the lightest in the test, is still a very light shoe. They weigh 1.5 pounds in size 7 and feel that the extra ounce or two was worth the added performance benefits.
This shoe weighs the same as some of Salomon's trail running-specific models, and it feels light enough to run in without weighing you down.

The lugs are well-spaced and deep, and gave us good purchase on a variety of terrain.
Photo: Cam McKenzie Ring
Water Resistance
This pair has great water resistance. The synthetic mesh upper repelled water well and didn't absorb any during our water tests. Sometimes an upper gets saturated, and while the waterproof liner might keep your feet dry, you'll be walking around with a heavier shoe. This wasn't the case with the X Ultra 3.
The ankle opening is 3 and 3/8th of an inch off the ground. That's higher than many lightweight models, but not quite as much as shoes with burlier or more cushioned soles. The difference is slight, but sometimes it's that quarter of an inch that makes the difference between a dry and wet sock. The gusset on the tongue came up high though and did stop water from entering there.
Durability
Sometimes a lightweight shoe sheds the ounces by compromising the strength and quality of materials that make it more durable. That was not our experience with the X Ultra 3. They held up well in our testing and still look almost new after months of use. The synthetic uppers are abrasion-resistant, as is the lining, so you won't get any annoying pills on the inside no matter how many times you put these on. The front toe cap also helps protect the shoe from wear.
Our only durability concern is the Quicklace system. While we didn't notice any issues during our testing period, online user reviews are full of complaints about the lack of durability in some models. The laces either break or in some cases tear out an eyelet. All but the bottom eyelets on the X Ultra 3 are reinforced on the inside. Maybe Salomon thinks that the first eyelet receives the least amount of pressure and that it wasn't worth reinforcing that one, but it does seem like an odd choice. You can buy a replacement kit for a few dollars if your laces do break, but if you pop an eyelet out, there's no good way to fix it.

The bottom eyelet is not reinforced but the rest are. Hopefully that one doesn't wear out, as the thin laces do exert a lot of pressure on the eyelets.
Photo: Cam McKenzie Ring
We didn't have any issues with the release tab sticking, which did happen on the only other model in our review that uses this system. If you love using a speed lace system, Salomon seems to have it a little more dialed than other brands do at this point.
Value
This pair is definitely on the expensive side for a hiking shoe. It is a high performer though, so if you're looking for a lightweight pair for moving fast on the trail, they just may be worth it. If you don't see yourself needing the Gore-Tex liner, then a non-waterproof version is available for a little bit less.

Heading out for a combo hike/trail run? These are the best choice!
Photo: Cam McKenzie Ring
Conclusion
The
Salomon X Ultra 3 is a fantastic hiking shoe that's built for fast hiking. It's comfortable and supportive and has excellent water resistance. We like this shoe for all of our day hiking needs but would choose something else for overnight trips.