So, it's time for Gav's Fortress Forever (FF) versus Team Fortress 2 (TF2) showdown post.
First, a bit of background. Before Counter-Strike became the most popular PC team-based online shooter on the planet, that crown was held by Team Fortress Classic, a Half-Life mod which was itself a remake of an old Quake Mod named Team Fortress. TF/TFC is class-based, each class having strengths and weaknesses (the Heavy Weapons Guy is slow but well armoured with a big gun; the Scout is fast, but lacks armour and firepower). The pace of TFC is slower than deathmatch games, and therefore less "twitch"-reflex based, with a bit more emphasis on being cunning.
Back in the day, I played TFC a lot, and only gave up when the online community withered to the point where it was almost impossible to find a fun game. So I'm definitely in the market for a follow-up (well, I was, because I've now bought/downloaded both of the main contenders).( cut for the sanity of those not interested in online multiplayer shooter games )
To summarise the two games: FF is effectively TFC with the annoyances fixed. TF2 is a much more radical overhaul of the whole Team Fortress concept.
If you're an old TFC hand, appalled at what Valve have done with TF2 (no grenades!? teleporters?! minimal CTF!?) then go check out FF. Ditto if you're an old-school FPS player who finds TF2 too slow-paced.
If you're generally intimidated by online multiplayer shooters because the twitch-reflex gamers hand you your ass on a plate 2 seconds after you spawn, try TF2. It's a slower pace, and most classes reward tactical cunning more than twitch reflexes
If you're new to this whole Team Fortress lark, then I recommend you try both. While there are many similarities, they're rather different games, and different people will prefer different flavours.
My preference is for TF2. This is mostly due to the "fun" factor, but I think it's also down to the TF2 developers evolving the game in pretty much the direction I wanted it to go.
I really feel for the FF developers. They've worked hard for the last couple of years producing a really high quality multiplayer mod, which makes numerous improvements to the TFC game style yet keeps the overall feel, only to release it right in front of the oncoming TF2 juggernaut. I hope they don't get squished, it's a damn good mod.