> I like them all.
> Super UFO
> Uses multiple ROM formats, but not SMC which is the most popular. It's inexpensive but has floppy only loading -- sounds like that's not for you.
> Super Wildcard DX2
> Easiest to use. Uses SMC format ROMs. Supports 64Mbit dram. Parallel port makes transferring from the PC easy with vgs2000. Can use old model ZIP 100 drive to store games. Add-on Disk Dual lets you load from CD-ROM or Hard Disk. It's the most expensive unit. Recently I've noticed some instability with a couple of games on the DX2.
> Game Doctor SF7 / Professor SF II
> Doesn't use SMC format ROMs, it uses Game Doctor format, so you'll have to convert almost anything you don't dump yourself and conversion can be difficult for some games because the conversion programs have bugs.
> Naming convention of the ROMs makes it more difficult to keep track of the names of the games (SF#####).
> Supports up to 128Mbit memory.
> It has a parallel port to make transferring easy. It supports a proprietary CD-ROM drive unit if you can find it (usually difficult).
> They are all good units and depending on what you're looking for one or the other may be better for someone else. From your list of big things my recommendation for you would be the DX2. It's the easiest to use, convert, has the most options for transfer.