The Right Tool for the Right Job
The selection of belay devices has grown large and specialized enough that it's now essential to chose the right tool for the right job. Despite what the marketing material might tell you, there is no device that can do it all (at least not well). Therefore, we believe the best way to approach a belay device purchase is by first deciding what type of climbing you intend to do. Then we can explore the devices suited for that discipline.
Black Diamond ATC XP best, but the Petzl Verso or any other basic tube is sure to fulfill the needs of most beginner climbers.
Cragging: Sport, Trad, or Gym
No matter the type of protection or the medium, climbing single-pitch routes places certain demands on a belay device. Falls and resting on the rope are common, so good braking assistance and lock-off strength can make belaying a lot easier. Partners also frequently ask to be lowered to the ground instead of rappelling. Finally, weight and size can be overlooked in favor of convenience and toughness when you don't have far to walk.
Petzl GriGri 2. It's got the smoothest action of any assisted locking device combined with a reliable catch and pleasant lowering. Of course it's limited to single ropes only, but this doesn't matter when the belayer's feet never have to leave the ground. We've sometimes heard friends foregoing GriGri's for trad climbing because the static bite, they claim, will increase the impact forces on gear placements. In our experience this concern is overblown for the majority of trad destinations. Ropes stretch and belayers can move to provide a dynamic catch. An extra inch of rope slipping through a belay device should only make a difference with the diciest of placements in the softest of rock.
If the GriGri 2's $100 pricetag seems outrageous to the occasional cragger, you might consider a passive assisted braking device. These will provide some extra bite and good lock off strength but for half or less the cost. The drawback though is in smoothness and ease of use. Our favorite of these was the Edelrid Mega Jul which won't break the bank at $34.95.
Whenever you get a rope length off the ground, it's wise to have a device that can get you back down. We're of course aware of walk-off routes, simul-rappelling, and other rope tricks to descend a doubled rope on single strand, but we're trying to talk about belay devices with two slots for standard two strand rappels. Multi-pitch climbing can also be made easier with devices capable of belaying a follower (or two) directly off the anchor. Although we know many multi-pitchers don't use auto-block mode, we believe it can greatly enhances your comfort and see few reasons to not use it.
Black Diamond ATC Guide. Nothing stood out in particular, it just had the best overall performance across our six comparison categories. Two of its competitors, the Edelrid Mega Jul and Mammut Smart Alpine, both offered tempting braking assistance for lead belays but had deficiencies in auto-block mode and rappelling, respectively.
Hard Free Climbing or Big Walls
All climbers need to be safety conscious, but we realize some are willing to sacrifice extra comfort, money, and convenience to further minimize their risk. For these climbers we suggest checking out the Camp Matik. Although we believe safety is most dependent on the skill and attentiveness of the belayer, we see some validity to claimed benefits of the Matik. The Matik features an anti-panic lowering mechanism that locks the device when the handle is pulled too far. It also has a gradual camming action that could theoretically lower impact forces. We don't feel these two features are necessary for most users or warrant its $200 pricetag. However, we understand that some shoppers will disagree.
Two ways to improve safety that we think all climbers should embrace are belay gloves and belay glasses. Gloves not only save your hand strength but allow you to stop an out of control rope without getting terrible burns. The benefits of belay glasses sound less significant but in our experience are just as dramatic. They use prisms or mirrors to reflect light so you can keep your neck in a neutral position while watching your partner climb. The side-affect is you become a much more attentive belayer. No more neck pain and no more surprises from unannounced falls.
Belay Device Outlook
At this point, we at OutdoorGearLab have been reviewing belay devices for seven years and surprising little has changed in that time. The Petzl GriGri (with an update) remains our favorite while the Black Diamond ATC Guide and Petzl Reverso continue their fight for second place.
It seems like every year a new device gets released and for awhile there's a buzz about how it's going to take over the market. Quickly though, early adopters discover the disadvantages the manufacturer failed to advertise. At best, the product becomes popular within a narrow niche, but more likely it's forgotten and quietly taken off the market a few years later.
Our best buying advice is thus to be skeptical of the 'latest and greatest' belay devices. This is one piece of gear you don't want to mess around with and design flaws can sometimes take years to identify. Furthermore, a UIAA certification alone doesn't ensure your safety.
Whatever device you choose, learn all you can about it. Read the manual. Take your belay responsibilities seriously. You only have to thumb through Accidents in North American Mountaineering to realize how dangerous this sport really is. Our attitude now, after spending the past six months again examining the latest crop of belay devices, is to stick with the popular, well vetted, stalwarts, read the manual carefully and never take a hand off the brake.