It really depends on what you like to do. If you are just checking email it really doesn't matter, but if you are gaming, downloading and streaming movies, you need a good one.
I just need a few more bars about 50 yards away from the router. So I can check emails and stream tv while I'm working. Nothing extreme. I appreciate the feedback
I bought a Linksys unit from Sam's. Got it hooked up, really didn't help. I would not recommend that unit. I think BHelm is giving you good advice. Buy one, see if it works. If not, take it back.
The extenders don't work well in general. The ones I've seen but never used personally didn't do much of anything. Maybe they are better now.