Wow! I've been posting all morning about my transition from a MOTU 24IO to 2 Roland Studio-Captures! It seems MOTU is dis-continuing PCI support. That being said, I'll answer your questions,
1- Sound quality is phenomenal!
2- I never had any sample rate problems with either the 24 or the SCs. The sample rates for the SCs using MME drivers are full spectrum, most any rate you want up to 192 if I remember correctly. The only rates you have in ASIO is 44.1 and 48. I think my MOTU was the same way. Using Cakewalk, I run ASIO drivers for lowest latency on my system. Some others have better results with MME or WDM. I use 24 bit, 44.1k. I can get a little lower latency if I switch to 48k but 44.1 works great for me and there is no conversion other than bit rate.
The SCs also have a direct monitoring knob on it so you have zero latency by mixing the input of the interface with the output of the software.
If you will do a search for info on the SCs in the forums here, I did a long descriptive review of the setup of mine when I bought them last year. I couldn't be happier with them.
And NO, I'm not a big time big budget producer/musician. But in the years of my playing live and sessions I have worked with some pretty big heavyweights in the business. I have been professionally performing and recording for more years than I like to remember. I do all genres of music in my studio. Commercials, radio and TV, rap, rock jazz, you name it.
I tell you now that if I had to do it again, I would run to buy the Studio-Captures! They are that good.
http://forum.cakewalk.com/Sidroes-Studio-Captures-and-Sonar-X2a-Adventures-m2855225.aspx