best wordpress theme for review sites?

Thereis no "best theme". Anything that's clean, professional, functional, and easy to navigate will work well.

I don't do review sites, and although I'm somewhat well versed in WordPress, I don't pretend to be an expert on all the themes out there.

That said, I would venture to say that it depends on what type of reviews you plan to do.

If you're mostly doing video reviews, find a theme designed for the posting of mostly videos. If you're doing written reviews with no or few pictures, look for a theme geared towards writers. If you plan to include a photo with every written review, one of the photo friendly themes should work. In fact, if you set it up correctly with great photos and a good slider or gallery, the photos can do a lot of the work driving traffic to your written reviews.

I'm in the process of starting a new blog and I chose Omega as my theme. What I like about it is that it's good for combination text/photo posts and best of all, the theme will display even large photos at a consistent width, without "breaking" the appearance of your blog.

Here's a link to the demo of Omega theme showing how it works with photos of different sizes: Markup: Image Alignment. Note that I am NOT the developer of Omega nor an affiliate nor anything else. In fact, the Omega theme is free. I'm just trying to help. Best wishes to you no matter what theme you choose.

You might find this blogpost useful. It's a list of themes that can be used for affiliate websites including review sites.

Personally I'd recommend the Splash theme.

Hope it helps

I suggest you to take a look on 8 WordPress Themes And Plugins For Creating A Review Site - WPMU DEV. You will find some nice themes for review site.