Geez, I know I'm gonna get flamed or blacklisted here, no matter what I say. But I'll give it a try nonetheless

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Be warned in advance that AH2 doesn't make a good first impression on a lot of folks. This is because
AT PRESENT, AH2 adds no new gameplay options to AH1. It's still exactly the same game at the bottom line. On top of this, the new graphics require about twice the computer horsepower you need for AH1. While you can get a decent FPS out of like a 1.7GHz, this comes at the expense of making buildings be invisible unless you're right on top of them, so air-to-ground work goes out the window. You have to have enough computer to have a good FPS with the buildings visible at tactically useful distances. So if you just take a quick look, it appears that AH2 is just AH1 only with new, computer-bogging graphics, less planes, and difficult taxiing. Many folks don't think this is a good enough reason to have to buy a new computer, so there's a fair amount of hate and discontent right now.
However, AH2 has a lot of improvements over AH1 that ain't obvious to the casual observer. Primarily, the flight and damage models are all new, and they have a number of spin-offs that add new features to the game and improve on old features. But the main thing is that the new game engine provides the potential for a lot of additional gameplay options and new features down the road. That's the main reason why HT did AH2--he'd taken the AH1 engine as far as it could go. Thus, once the basics of AH2 are complete, look for a lot of cool new features to start appearing, not to mention the whole TOD thing.
So that's the situation. Right now, AH2 offers far less than it's total potential. While even now it's got some nice new features, much of HTC's work has gone into things like the new flight model, where the differences to AH1 are very subtle except in certain flight regimes. The new graphics mean that unless you've got a 2.2GHz or better CPU, along with probably a good Nvidia card, you'll almost certainly have to get a new computer for AH2 to be playable both air-to-air and air-to-ground. If you go by what AH2 offers now, you could well think it's not worth the expense. OTOH, if the full potential was actually available already, you'd probably already have a new rig on order without a second thought.