I too am using the Delta 1010 w/GS3 -- and Sonar 3 PE on a 2.4ghz PIV w/1Gb RAM.
No problems whatsoever - no hiccups or timing errors, and the GSIF-2 driver is rock solid. I love being able to bring audio from my sequencer re-routed through the 1010's Monitor section and into GS3 for processing with Gigapulse. Very cool!
M-audio is one of the best in releasing updates and drivers for their gear in a timely fashion. I have no complaints. I think you won't either.