Aw, you guys are disapointing me!!
I'm not a big fan of multiplayer FPS games, so maybe that's why I like TF2.
Bought the Orange Box for Episode Two and Portal, but TF2 grew on me. It's a great game to just hop into and relax for a bit, and there are enough classes and weapons to find a few combos that suits my mood to either goof around with or play to win with. TF2 has always been more about having fun than simply dominating with kills, and the game design reflects that.
It totally is not realistic, that would have just killed the game as there's no way any of it could be realistic. Realistic shooters are a dime a dozen, but even then it still amazes me how many people stick to playing CS and CS:S... I used to play CS around 1.6, but shortly after CS:S came out I just got bored with it, and CS:S was identical save for slightly higher graphics. There's nothing to the game itself except who knows the map chokes and has the best crack shot skills. I never played the original Team Fortress except once, but I'm glad it wasn't a sequel.
So if you're looking for a realistic shooter I'd suggest skipping TF2, this is a completely different style of FPS. TF2 is more about map control because the battle always is moving, it isn't always in the same exact spot like CS or CS:S. Strategizing or simply working with teammates for the objectives is key, and the game mechanics completely de-emphasize crack shooting. I've found that my background with RTS kinda helps with this game. Although if you're good with on-the-fly projectile trajectories and reading players, well, you'll have lots of fun with the weapons that don't actually use bullets or explosives.
I gotta be honest I didn't see this coming. However with the decline in players and so many other games going free to play, it's no surprise that this happened. I went to go play this maybe a year or so ago and the amount of players was just horrible, even at peak hours, seriously I find more people playing CSS then I do TF2 most days, yet a lot of people say they play TF2 what's up with that?
Actually, TF2 has had about the same number of players as CS and CSS for several years, although I don't recall the exact rankings to quote them nor when TF2 reached that point. Anyone can view current Steam player statistcs here:
http://store.steampowered.com/stats/ Since the update you can see the numbers have obviously changed, though...
There are just so many servers to choose from that I can see how ya might think there weren't enough players! Honestly the servers can make or break the game experience... I've played on servers full of nothing but totally clueless noobs to servers full of people who's skills will show you just how good you really are. As with any game it takes a bit of trial and error to find a good server... but there are hundreds, if not thousands of steam groups and multi-game communities that run their own servers out there that usually have fun servers with good running banter to game on...