After finishing up the Conspiracies mod, I finally went back to actually finish the last mission of the original OFP campaign. For whatever reason, I stalled out on that one but have spent lots of time with single missions and just playing in the editor. Even with its age I still enjoy it thanks to the mod community. Not bad for a game I got on ebay for about $1 with all expansions (Think it cost more to ship it than my final bid).
Even though I stalled out playing it, this is still one of my favorite FPS games. While I prefer RPG-FPS like Deus Ex or System Shock 2, I also enjoy the tactical games. I played Ghost Recon first as OFP was too much at the time, but once I was used to the squad play in GR I dug back into OFP. I've done the 1st campaign, some of the single player missions, and lots of custom mod missions or just random editor play.
Yes, the game can be a bit ugly and clunky, but there is just so much to do from infantry to tanks to air combat. If you don't like the setting, just download some mods to change it (WW1, WW2, Vietnam, Cold War, Future Combat, etc.). Even a Mad Max style mod which is the closest to Car Wars/Autoduel I can get besides Interstate 76. Even if you just want to play the original campaigns there are good mods to change the units to look better (I love the models by Sanctuary).
Besides ArmA, I really don't think there are other games out there like it. While there are some tactical games with vehicles, they don't have the scope and moddability of OFP. With OFP, I can open the editor, then either edit an existing mission or just plunk down troops and see how it all goes. Of course, I could do scripting to get even better missions, but I like that it lets any skill level use it. For a change of scenery, just download another island someone has made and see if there are missions for it or make your own. So while some areas could be improved past what Bohemia has done with the patches and users with mods, I still think its one of the best tactical FPS out there.
Now to play the expansions and the multitude of user made campaigns/missions I've downloaded with a liberal use of the savemission cheat so I can have unlimited saves. It's just so easy to die in this game so I don't want to worry about having only 1 save.