I remember way back... I was beta testing Nuendo 1.52 for Mac OS and Nuendo for PC for Steinberg and RME sent me a Prototype (think i was a 9652) PCI card...
They sent 2 EPROM's that I would swap on the card (1 for PC, 1 for Mac) and I tested that card straight for about 5 weeks... the tracks it produced were so clear (no digital "smearing/jitter"); the bass warmth & response far exceeded all other cards we were testing at the time (Delta series, motu, etc.); It was, by far, the winner in in all categories as far as driver stability & the quality of recordings (D/A converters are awesome... probably only surpassed by Apogee at the time).
I would recommend an RME interface to anyone that can afford one, they have come down so much over the years... an 8 track "Multiface" with a PCI card will set you back about $350 to $400 on ebay these days, but that was a fraction of the original cost.
if you are a very serious producer under OS 9 and want to multitrack a few instruments at a time then RME is for you...
if you are a solo artist on a budget, the M-Audio 2496 is still the clear winner ($89 to $99), great converters, MIDI included, 2 track analog or 4 track using analog and digital ins at the same time)