This review is based on months of testing with 17 of today's most popular belay devices, but it rests on an 10-year foundation that goes back to 2009 when we first started examining the product category. While the belay device market has changed considerably in that time, the results haven't so much: the GriGri (with updates) remains our favorite.
Four different climbers have played the role of lead reviewer of belay devices over that time, and it is remarkable how little variance they have found in their testing. This isn't a case of advertising dollars holding sway either. All the belay devices tested were purchased by OutdoorGearLab on the retail market, and the reviewers had no financial incentive to score any product over another. Our conclusions are based entirely on our interactions with these devices. We sought out opinions from friends and acquaintances, but anything we couldn't prove ourselves we either left out or mentioned the source. Here's how we specifically tested each model for our various comparison metrics.
compared the relative braking strengths and device engagement for various assisted braking devices. With the increasing popularity of passive assisted devices, and some manufacturer claims that they perform as well as an active device, it was interesting to see some lab tests that compared their effectiveness and showed their weaknesses.
We rappelled and lowered with each device dozens of times, and would switch devices between routes to get that side-by-side comparison of how smooth they felt relative to each other.
For this category, we noted the smoothness of the pull and the complexity of the belay technique. We tried to keep an open mind with each device and not judge it by our first use, but rather how it felt after multiple days spent using it and practicing the proper technique. We should note though, that due to the ubiquity and popularity of the Petzl GriGri for the last twenty-plus years, most of our testers have been using that device exclusively except when multi-pitch climbing; it is "interesting" for them to try out new belay techniques again!
Weight and Bulk
This was likely one of the least "subjective" metrics in our testing process, as the scales don't lie! We weighed each model on our digital scale and also considered how large the unit was. Some results were surprising. We thought the Mad Rock Lifeguard would be significantly lighter than the GriGri since it's so small, but it's 5.4 ounces isn't that much weight savings over the 6.3 ounce GriGri and 7.1 ounce GriGri+.
In the end, the right belay device for you is whichever one keeps you safe. You may disagree with the final standings, but we hope you found our analysis informative.