I would ask to see a repaired one first so that you can see what quality glass you are getting. I have read reports of the cheaper glass having a hue/color cast.
OK.. I just repaired my daughters iTouch 2nd gen. And now that I have done it.. if i were to try it again I could do it in 10 minutes and after a few more times.. I probably could do it in 5 minutes.
This is based on getting the bezel and glass and home button all-in=one replacement. The tools I bought for the job were a complete waste. A guitar pick (which actually was one of the tools in the kit) and small jewelers watch screwdriver (flathead) were all I used.
Skip the tools and the cost is 15.39 with free shipping since I bought some other stuff too on Amazon.
I put 2 veeerrry small nicks in the lcd with the screwdriver... but when the unit is on the light makes them invisible. Actually.. I just checked and you can't even see them when the unit is off. Whew.