This is a really beefy tool that's designed for the workshop rather than the road. A decent set of ball-ended keys would still be my first choice, though, especially for workshop jobs; Park's HXS1 set gives you nine sizes for the same money.
This tool does have some advantages though: it's much stiffer than a single 8mm key which is good for crank bolt work, and you can fold out the 6/8mm keys into a T-bar handle to tighten difficult bolts quite effectively.
There's a dual Allen key head at either end, with the 4, 5, 6 and 8mm sizes ideal for most bike tinkering. The design means it's better for awkward bolts than most multi tools.