Stick with name brands, APC, Belkin, Cyberpower are the popular ones on newegg. I don't know of any sites that specifically cater to UPS reviews, but the [h] can help you out with selection if we know your loads/needs
Stick to the popular brands and make sure it has the wattage you need. A UPS is meant to keep your system running so you can save your work and shut down, even if it's for five or ten minutes.
Also look into a UPS with voltage regulation/stabilization.