I bought a PC-FX about a year ago, and it's a neat thing to have. It hasn't seen a lot of playtime to be honest, although it's seen WAY more than my 3DO. For better or for worse, this is one system where as soon as you start a game, you feel like you're blasting off into PC-FX Land, a place like none other.
You better like Japanese "gal-games" though. Even if the real number of dating-sims on the system isn't so huge, the degree to which the library in general tries to sell itself with cute anime girlies is a little unbalanced, to say the least. It's also a little embarrassing to try to show and explain to people. Playing alone, I often find myself asking "WTF am I doing?". Maybe I need to chill out, but I've been put off from more than one game because of this.
On one hand, the PC-FX still has its moments, owing mostly to Zenki, Zeroigar, and all the games that have fairly well-animated cutscenes. On the other hand, even with price and language issues set aside, this is one of the last underdog systems I'd ever recommend to anyone.