I bought this tool because I now have an ebike with an ebikemotion motor in the rear hub. Removing the wheel to change a tire requires an 8mm hex key. This one fits and works fine. I have also meant to carry a chain tool, ever since a friend's derailleur hanger broke in a triathlon, and a spectator with a chain tool turned my friend's tri-rocket into a carbon-fiber fixie, but at least he was able to ride to the finish. This tool is solid, but also flat, so it takes up little space.
This is not the lightest multi-tool, by far, that I've owned, but it is one of the most complete and useful tools I've found. If a few extra grams is a major factor for your purchase, Crank Bros. makes a slightly less robust tool, the Multi-17, but if not, this tool packs just about every thing you could need for a breakdown on the road.
It has a quality feel that instills the sense of a quality piece, which also gives me the peace of mind to know I won't be left carrying my bike several miles down the road if something goes south on my bike.
Given the number of tools, Crank Bro's did manage to squeeze them into a fairly compact package, Also useful, is the light weight aluminum carrying case that will keep your tool dry and clean. It adds another couple of grams to the overall weight. The case will also keep your tool for handing up on other objects whether in a bag or your pocket.
In summary, if you're the type of rider that has to shed every single possible gram of weight, this probably not the multi-tool for you, conversely if you need a solid, well made tool for most possible situations and a few extra grams is not going to have you look at another tool, this is one quality piece of kit, especially for the money.
I purchased this for a bikepacking trip. I needed something that was relatively compact and had all the pro tools I'd hopefully need. It is very well constructed with super nice heft. It looks cool and has a nice lightweight case. I used the Allen keys a few times - they work.