I don't tend to buy games(MMOs at least)that I haven't been able to test beforehand.
I was in LOTRO SoA beta for 5-6 months before that launched, and I ended up buying the Collector's Edition of LOTRO SoA(EU side), it included a lifetime subscription.
I had a trial of AoC and thought, "ok, I can spend a few quid on this game, it's not the best game, but hey, it's amusing me sufficiently at the moment", so bought it for under £10.
I wanted into SW:TOR beta, because I wanted to see what it was like before I pre-ordered.
It took me until the stress test event to get invited, and then I got invited again for the last weekend test, and after that, I decided I wanted to at least play for a few months, so I pre-ordered it last monday, but only got my pre-order code from zavvi.com thursday.