I'd say it's as easy to use.
As for minimum specs, I *suppose* a P2 300 would work just fien with it.
To understand what I mean, d this (this will work even on my P133
): Download SIDPlay for Windows, and a few tunes in SID format that you know well and like.
Load'em up in SIDPLay, hear them for a while.
Then go to the Emulation option, and choose to use the reSID engine. Hear them again, hear the difference
As I said, teh difefrence will be more noticeable in tunes that make heavy use of filters. Great Giana Sisters is one good example.