In short, Warhawk is very fun and addictive if you like games such as Battlefield 2 and the SOCOM series.
In length, Warhawk has a solid framerate, relatively little to no lag on dedicated servers, good (not very good or great) graphics, great sound/music, very large maps, great gameplay, and if you play long enough, you'll realize it has a somewhat varied and balanced system of vehicles and weapons (TOW missles and proximity mines needed to be balanced in BETA). It is a quick and easy game to start up and jump into, but has a somewhat long learning curve, especially if you want to get good at it. Like all great online shooters, Warhawk can feel very epic if 2 good teams play each other. There is a lot of strategy in games if played right by both teams. Warhawk flying is very fast-paced and exciting with enough practice and there is always room for improvement when flying. There is a deep reward system that will keep players playing and stay interested for a long time (being changed from BETA). Aside from Resistance, Warhawk probably has the best online communication system and sense of "community," and this was only in BETA form.
There are of course faults too from my experience in the BETA, not counting glitches. First and foremost, ground combat aiming felt very "floaty," and unprecise. Hardcore online shooter fans may hate this fact, but if you give it enough playtime, it really isn't that big of an issue. The action can get very slow and players may feel like they're not involved or needed if they don't take the initiative and play offensively. But if played right and against good opposing players, even ground combat can become very fast-paced and hectic. Even though I said that the sense of community was good, it wasn't something that can be compared to other great online shooters such as Resistance. In BETA, the clan size had a very, very small cap limit, was glitched, and didn't do much except to show a tag on the side of players' names. The voice chat was decent, but was in desperate need of a squad/open chat system. Although Incognito wants Warhawk to have a system of individual servers, a party system or at least a chat lobby for friends and/or clan members to gather before matches would be a nice addition from BETA. Most weapons and vehicles are balanced, but like I said above, TOW missles and proximity mines can be extremely cheap weapons that when used correctly in the hands of a good/great player, can rack up a ridiculous amount of kills. The overwhelming degre to which auto-aiming with the rifle and handgun can be a major turnoff for most online shooter fans. But I've come to realize that it is a necessity with Warhawk's system. Just try and team kill your teammate with a rifle or handgun and you'll know why the auto-aim is so heavy with those weapons. Also, the sniper rifle takes a lot of time to get good with and isn't as good as it should be, due to its inability to zoom very far.
Well, that's about it for my mini-review of Warhawk and my reasons for "what's so good" and bad about it. Remember, everything I wrote was based off of the BETA version. Incognito could have changed many things and would then invalidate parts of what I wrote. These are all my OPINIONS about Warhawk BETA.