Customer Rating: 
Summary: You'll feel better on the trail.
Comment: Like another reviewer said: this is not a replacement for a shop-grade tool kit, but I feel so much safer on my family outings knowing that this tool is with me.
I tried the tools out for fit on lots of locations and the Alien fits everything on my bike that I would be comfortable repairing in the field. Also, the chain tool that comes with it works like a snap. It comes in a dandy little sheath that makes storage easy.
Customer Rating: 
Summary: Good Tool
Comment: This tool fits a large number of items on my bike. I've used it for derailer and chainring repairs so far. I've checked the tool's fit on various parts and it seems to cover the components except for the larger ones like bottom bracket, headset or pedals.
While reasonably solid, it would be unrealistic to expect it to replace the tools in my shop-grade toolbox. It's made to go with you when you ride and improve your chances of riding back if something goes wrong.
Other good items to ride with...
-Tire Irons
-patch kit and/or spare tube
-pump
