For trail- and road-side adjustments and repairs, nothing beats Giant's Tool Shed Compact CT. This svelte take-along contains 2, 3, 4, 5 and 6mm Allen wrenches, Phillips and regular screwdrivers, a T25 Torx tool (for securing disc-brake rotors), an integrated tire lever and a chain tool. The Tool Shed Compact CT folds up nicely, too, so you can easily carry it on every ride.
The design of this chain tool is flawed. It works well to remove a pin and to insert a pin if you want the link to be permanently very tight. The little bar that would hold one side only of a chain link is designed too close to the end bar of the tool. So you can't hold only one side of a link and still push on a pin to make a link flexible. Hard to explain, but quite frustrating.
Bottom LineNo, I would not recommend this to a friend