If it weren't for the fact the m-audio quit supporting it, I would have recommended the Profire. At 64 samples, RTL is 5.8ms @ 64 byte buffer and 48K sampling.
I would like to measure this directly instead of relying on what the ASIO driver is reporting but I need to find a way to do that.
I am looking at the Roland units as well since m-audio dropped support for the Profire 610. I emailed Roland to see if they will support the Quad and Octa capture in Windows 10. I will report back if/when they respond. I am a little concerned as these are not new units and I am already am dealing with end of support issues with the Profire.