Different strokes for different folks, I guess.
I bought SF the day it came out, and I've played it for like two hours...just didn't care for it, last time I fired it up was back in March, and that just to do some framerate checking. Granted, I do make regular use of some of the weapons unlocks in regular BF2...so in my case you could say I spent $30 to unlock five weapons. I still don't feel "ripped off"...I really like those new weapons.
But I played EF quite a bit when it was released, several hours more than I did SF, and still jump in on EF maps when I see one come up in rotation. I think I got my $10 worth out of that booster, and I expect I'll get my $10 out of AF when it comes out.
And unlike the vocal majority in this thread and others, I've generally had no problems with the patches (other than the server browser hiccup with 1.3), and agreed with or at least understood the reason behind most of the gameplay changes.
So I feel no need to go grab a noose and string EA/DICE up....I've gotten almost a solid year of fun gaming out of BF2 and both released add-ons. That's a pretty damned good gaming value, with the hours I've played, that works out to something like $.02 per hour. That kind of money won't even feed a starving kid in Africa.
No other game I've bought in the last two years (and I've bought a LOT) has lasted me this long, nor gave so much value for the buck. Hard to get my panties in a bunch about patches and a few bugs when MY experience to date has been good.