The EZE eye lazer does work well on some bows... but doesn't work at all on others. It's not the end all be all that some people seem to think it is. I used to use it on a daily basis to set up bows... but you can do just as good of a job eyeballing the string, cams, arrow.

As far as the levels go... they work awesome.. I personally use the HTM string level



And a very similar level.. that allows you to adjust for nocking height..


This setup works very well.. and is a little more precise than the ones that just clip on the string... But they are also a bit more expensive.