It's hard to say who this game is really for, but for ex-PC gamers looking for a fix, it might work in a pinch.
On one hand CS was a simple and yet brilliantly executed game on the PC. It could absorb days or weeks of time as you tried to increase your skills and search for that elusive zen-like state where every shot hit a head and your kills to death ratio was 10:1 or more. But the game suffered from the drawbacks of PC gaming; namely, rampant cheating and crummy, immature competition.
On paper the idea of Counter-Strike on the XBox sounds very sound: Cheating (while not impossible) is more difficult in a closed system like XBox Live and the built-in voice support would be a welcome addition. Plus it was the most popular online shooter ever, so who wouldn't want it on their console?
The real problem is that all of these things are true to an extent but when you remove the fact that CS's real strong suit is really that it was a mod for a game that was already great and most everybody already had, and it was free. For the price of an hour's download over a decent broadband line you could be online and playing a terrific team-based game with minimal fuss.
So when you have to plunk down $50 for the same experience with the dubious control scheme of a ported PC game to the console control scheme and no real discernible graphic or presentation improvements, the end result is a slightly better environment (ie less cheating) for a slightly inferior experience at a much higher premium.
The end result of this is that CS's warts are more obvious and its strengths are more subdued. It still retains most of the flavor of the original game and as far as the rough translation from keyboard and mouse to analog stick controls go it isn't half bad, but the sum is something that is worthwhile if you have a group of dedicated gamers who enjoy playing together online already and you find it easier to use the Live interface than fuss with PCs but for most others is probably going to be either a mild disappointment or a lukewarm acceptance.
It's hard to imagine anyone having a very strong reaction to this game, in part because it simply is what it is: A cash-in on a very popular (but not necessarily brilliant) PC game with an acceptable but by no means exceptional port.