Excellent features, but having used the Sky and Sony TV interface, I personally found the User Interface frustrating. Didn't help that I didn't get a manual on purchase, but even so these things should be intuitive. Really frustrating learning curve that I feel is a design problem not a user problem!
It's small things that make a difference, e.g. the TV guide doesn't have a page up / down feature. It took a while for me to discover the 'find' feature (searching for future programmes) - though now I have, it's great. But it wasn't where I expected.
Still, it's got loads of recording space, does exactly what it should, and the features are very good. They could just do with taking a leaf out of Sky's book from a UI point of view.