Originally Posted by Retro-Nerd
I prefer the MMCReplay, because i want to to use my real 1541 II drive to play C64 games.
You can write d64s out to disk with a 1541 Ultimate too. Rather than connecting the 1541U directly to your computer's IEC port, connect it to a disk drive and connect the disk drive to your 64. If your disk drive is device 8, assign a different number to the 1541U and away you go. You can also create d64s. Really though, what's the point? You have full compatibility with the 1541U. Hell, it even makes the same noises as a disk drive.
The 1541 Ultimate blows the MMC Replay away in every way.
Disclaimer: I may be bias as I'm involved with the development of the 1541U.