H'lo, Karalie,
I have been thrilled with a Steinberg MR816x.
I've owned a SeaSound SoloEX, an E-mu 1616m, a MOTU 828mkII, and the Steinberg MR816x.
The SeaSound was very good, as I remember it, but that was along time ago...
The E-mu was purchased after a LOT of research, and sounded very good, but the %*#@% crashed morning, noon, and night, and will be the last thing I ever use from Creative/E-mu.
The MOTU made my singing sound good; my singing A'INT good. The MIDI side was defective. Returned.
The MR816x just sits there and does every thing I need it to do; audio from my Kurzweil K2600, Omnisphere, and Trilian, and recording from my mics.
I can only crash 8.3.5x64 by doing a lot of piano-roll edits W/O saving, and then only once in a while.
I have read revues comparing with the RME 400 or 800 (don't remember which), which ranked them about equal as to AD/DA and pre-amps, but please do your
own research, as the newer RME units may have newer AD/DA's and pre's. You will need to use an external MIDI interface; I have a Cakewalk/Roland UM-3G which has been another install and forget piece of gear.
As to sound, I rate the above interfaces:
1) Steinberg MR816x.
2) Seasound SoloEX as I remember it.
3) E-mu 1616x.
4) MOTU 828mkii.
If I had to replace the MR816, it would be with another one, or an RME or a Metric Halo.
Hope this helps,
Tony