its going to be SCSI only, I could have given you my LS-20 but then its not worth it either.
The LS-10 will do OK with negatives and isn't too bad, but you'll absolutely need that SCSI. Are you using a laptop? If so and IF it has a PCMCIA slot you can get a SCSI card for that cheap off ebay. ONLY get the Adaptec one.
My advice to you is don't put much effort into it and get an Epson 4870 used. It will do USB 2 and one of the reasons my LS-20 is on the shelf is that the Epson 4870 scans better in every way you look at it.