Get the $2 ones. I just got one shipped from China for 2 bucks total. Its awesome. I didn't expect much, but it is really smooth, thin, and was easy to install. I haven't had any problems with the finger print scanner. It might even work better, but I'm sure the mileage will carry with user. I never use the fingerprint scanner. I'm not sure of the weight, but now that you mention it my phone does feel a bit heavy.
I haven't used one of the name brand ones though. I'd be curious to hear from someone who's used both.