Hey no prob...
By latency do you mean for general monitoring or running things like Amplitube?
For general monitoring there's no latency at all - the MOTU interfaces have their own hardware monitoring system and mixer built in so you are monitoring off the hardware before it enters your computer. I think most other interfaces do this now too - it's pretty essential. Latency during monitoring is hideous.
If you are wanting to monitor with effects or things like Amplitube, Guitar Rig etc, the latency will depend on the software itself and how fast your computer is.
I have no experience with PCs but the MOTU drivers have been rock solid on the few of Macs I've used them with.
Crustaceo ergo sum