I've played OFP since the demo came out way back in 2001, which I remember spending most of an evening trying to survive. By the start of the small hours of the morning I'd managed to get down the hill with most of my team alive and avoid or destroy the BMP's so we could get to the beach extraction point. The demo pretty much sold the game to me.
A lot of memorable moments such as dodging the snipers and BMPs in that nightmarish After Montignac mission (if you failed to take the town) and the annoying Cobra bug in Pathfinder, which was actually one of my most favourite missions. The Spec Op missions were sometimes incredibly difficult but without a doubt were some of the strongest missions of the 1985 campaign. I also tried a bit of editing and made a few missions though they were never that good and so spent the odd weekend playing recommended missions off the now sadly defunct Avon Lady's FAQ site.
I missed out on the first Arma due to not having a PC to play it properly and the demo was pretty much unplayable due to the lag.
So I've not played Arma 2 much due to the performance issues until this weekend's patch but now I'm stuck on Manhatten because my team mates always seem to die too easily. The campaign so far feels a little weak against OFP, no denying it is still good but the 1985 campaign had much better atmosphere around it.
I haven't played online yet in any of the games and to be honest I've not really been that interested in online gaming since the main UK leagues for Quake 2 Capture the Flag died out in 2003. Most the games I've played since online such as the sequels and COD4 just haven't lived up to the experience I got from Quake 2.
Anyway hopefully the next patch will bring some AI improvements now that performance has been worked on.
Finally I'm glad we still have games like this around as a lot of niche games seem to have declined or lost their appealing aspects such as the Rainbow Six series for example. It's good to see this is still sticking to it's roots from OFP.