> do current saturn emulator really playable?
There are two Saturn emulators that I think are worth using.
One is GiriGiri/Cassini, which was the first Saturn emu to have decent performance and compatibility. The performance is erratic, though. Some games will run very well on a low spec system and others will chug even on a hot rod. The graphics are accelerated/hi-res.
The other is SSF, which seems to be a little less compatible than GiriGiri (though in the same ballpark, I think), but when it runs something the graphics seem to be alot more accurate, and the performance is very good, and it can run full speed on a reasonable system. The sound emulation, however, is not very good. Music, both MIDI and redbook, is fine, but alot of games seem to have no sound effects, or sound effects drop in and out throughout the game.
Right now, I lean toward SSF. It plays Cotton 2, Guardian Force, Silhouette Mirage and Radiant Silvergun full speed very well.