I'm very happy with the RME - it works with no fuss, the mixer matrix is excellent for home studio stuff and it sounds pretty good too. We had a Motu 828mk2 or 3, I think it was the firewire ports that were dodgy but it kept losing connection at inopportune times! Looked a lot tougher than it was.
Yeah it's a PC - think the case is about 15 years old now (maybe more!). Everything in it has been changed at least once but the problem remains... Admittedly it's inaudible at normal listening levels but it shows up on recorded inputs and layers up louder and louder that way. It isn't there with the isolated gear but it's irritating to remember to unplug stuff as USB midi and USB power is ubiquitous now.