Having never played the Xbox 360 version of Gears, I have no basis on which to recommend the PC version to a current owner of the original. I can, however, say that Gears of War qualifies as a must-purchase if you don't already own the game and the idea of a semi-third-person shooter appeals to you at all.
As a certified first-person junkie I found myself disliking the viewpoint Gears offers for probably the first fifth of the game. Progressing, I grew much more comfortable with the mechanics and began to appreciate the reasoning behind that decision (plus you always get to see how cool you look). The duck and shoot game play would be much less effective in first-person and that, in a nutshell, is mostly what the game is about. Quick button combinations will have you rolling and dashing like an action movie veteran in no time and, as a long-time Unreal series devotee, I really appreciated the implementation of double-tapping movement keys to perform many of them. Reloading your weapon requires precise timing. Doing it correctly will yield a quicker reload time and a damage bonus, but if you flub it up, you'll find yourself praying for a reload before you're totally overwhelmed by locusts. It's a nice minigame that adds some risk/reward depth to the experience.
Gears of War is a pretty linear game. Though you are occasionally given alternate pathways to take, you'll ultimately end up in the same location and nothing you can do during the game affects the unfolding of the storyline. The alternate routes do give the game a bit of replayability, as they offer a chance to take a different role in fixed scenarios. Pick one pathway and you may end up playing the role of the marine grunt, battling up close against unbelievable odds, while the other pathway may offer you the chance to dole out suppressing fire from high ground. These kinds of choices really shine in co-op play which is the method of choice in which to experience this game.
Teaming up with a buddy online will give you a chance to try out strategies that just aren't possible with your AI squad mates. Not to say that your computer controlled allies are hapless by any means… I found them to be much better than in most games that have tried this approach. In fact, they can't die in most chapters, so you can either plow ahead or hang back and let them do some of the rushing for you. The enemy AI is mostly decent too as they'll attempt to rush you if they have the numbers, flank you if the terrain is favorable, or toss a grenade into your hidey-hole if you get too comfy in one spot. There are occasional gaffes, but for the most part they remain solid.
The online experience is going to largely depend on its adoption rate. Gears ships with a whopping 19 unique multiplayer maps and five variations of deathmatch, which is pretty impressive considering the singleplayer campaign clocks in around 12 hours and has loads of replayability in co-op. For those that like to hunt for secrets, over 30 cogtags (similar to dog-tags of fallen soldiers) have been hidden about the game and you'll have to do a thorough search to find them all.
It's actually pretty amazing that the title is a year old already, because it still looks as stunning as most of the top PC titles being released today. The art direction overall is just outstanding and the character animation is superb.
It's true that the storyline in Gears is not going to win a Pulitzer Prize, but it doesn't really need to. It's unapologetically macho in its delivery and serves well enough to move you from place to place. Just be aware that you aren't going to be moved to tears or come away with a life-altering epiphany if that sort of thing is important to you in your games.
I'd be remiss if I neglected to mention the slight stutters during level loading which seems to affect some more than others. To me (AMD 64 x2 4200, 2 GB RAM, 7800 GT, Win XP SP2) it was noticeable, but didn't detract from the experience overall. Also in the negative column is the limited matchmaking – that is unless you subscribe to Xbox LIVE Gold, which I don't. You can find a few players online simply enough otherwise, but you can't escape the feeling that you're missing part of the game if you're a lowly free Silver subscriber. Be aware also, that as of this time, there is no dedicated server and I am not aware of any plans for one. Despite all that, there's a tremendous amount of fun stuff here and it's all beautifully done. If the gameplay I described sounds like your thing, then there's a good chance you'll enjoy it.