I'd think twice before using a domain with "ipad" or ipad2" in it. Since iPad2 was just your example, I'd suggest not relying on any domain containing a brand, product name, trademark, etc. Unless, of course, you own the brand or name.

Peace.

In order, my preference would be: iPad2.com, iPad2Review.com

The 3rd one is really weak, IMHO and I would instead look for something like:

ipad2x.com or ipad2z.com (since they are essentially the same as ipad2.com)

BTW, I know this is just an example you are using, but steer clear of trademarked names. Your business will be more bulletproof and you'll sleep better at night ;-)

Search engines (especially the big one) like quality content. The review site, assuming you've taken time to actually purchase the product yourself and you can write a unique, hands-on, first person perspective article that showcases the product's pros and cons (always be up front about the bad stuff as well as the good), then I'd say that's your best bet to gain favor in the SERPS.

suffix works better in my experience.