I decided to give Hawken a chance because I been looking for some new FPS to play.
I'll start saying the game works. This is important because the ammount of games out there who are buggy or dead is so big just being able to play without much hassle is a huge plus. Also, the tutorial teaches you how to handle your Mech which is necessary since the game has some mechanics you need to learn before jumping in the fray.
However, I feel there is not THAT much variance between the Mechs and the feeling of "sameness" hit me quicker than other games. But mind you, I'm the kind of person who don't like Counter Strike and Modern Warfare which are hugely popular so it's more of a personal thing than a game flaw.
Also on the personal side, I did not find the Mechs and weapons particularly pretty. I had a hard finding a favorite because all looked like a gray mess to me. I'm more of a Front Mission kind of person I guess.
In the end, I'd recommend mech lovers to at least give it a try. It's solid and delivery what it promisses, and the small touches like the cockpit view are nice. Sadly, it is not what I am looking right now.