In my opinion, the online PS series don't really have a place where they belong, their releases were always inconsistent.
PSO - Dreamcast
PSO ver.2 - Dreamcast, PC
PSO Ep 1&2 - Gamecube, XBox
PSO Ep 3 - Gamecube
PSO BB - PC
PSU - PC, PS2, XBox 360
PSU AotI - PC, PS2, XBox 360
Started on a SEGA console later with a PC port (I think that PC version was only released in Asia though), went to Nintendo and Microsoft consoles, then just Nintendo, then PC, and in the end PC, Sony and Microsoft.
Anyway, I'm fine with PC only, but would be nice if it was PC/PS3, and maybe XBox360, if Microsoft allowed their players to play together with PC and PS3 players (but seeing what happened with FFXIV, that's not gonna happen)...
But, if being PC only means that the western servers may keep up with the eastern servers in terms of updates, then I'm all for PC only. :>
For those that prefer playing with controllers, there's some fine gamepads for the PC, including some new ones that Logitech will be releasing soon, somewhat similar to PS3 controllers and their previous "Rumblepad 2".
Since this new controller supports Xinput, that means it'll work in any game that works with the XBox360 PC version controller (it also supports DirectInput, to work with older games).