In theory, it's a good idea. But like the other posters have mentioned, it's an uphill battle. In my experience (Application Developer), creating the content management side is easy. Creating the content and building a subscriber/user, that's an entirely separate -- and exponentially more difficult -- endeavor.
* How would you entice professional photographers to review equipment on your site? To start, I imagine this site would have low traffic and small user base, so for a professional photographer to take time away from their job, you'd likely have to pay them.
* How would you manage the content? Would it be a free for all, or would you have an administrator?
* What would be your source of revenue? Ads are great, but given the saturation of market (I mean, you're posting this idea through a competitor) I can't imagine you would recoup your investment (time, capital, etc) very quickly.
Frankly, this idea kind of sounds like facebook for photographers. Which, again, isn't a bad idea... but having built these sorts of tools in the past, I can guarantee getting it off the ground would be more challenging than you think.
Thanks for your thoughts! You're right, the primary factor in getting an idea like this off the ground would be finding the professional photographers to write reviews. I have access to this, so the secondary factor which comes up as you mentioned is of course SEO.
I don't believe revenue would be a requirement here, at least at first. Perhaps referral links to cameras on B&H or something could be one source, which wouldn't be banner-based (ldeal). What do you think?