I used numerous Nuby cups for its convenience. I am lucky that my DD will use just about anything, so there was no problem for us to use Nuby's.
The only complaint I have about Nuby cups is that while they say they don't leak, they DO! So I used to put it in a plastic bag but then the bag would get soggy and horrible.
Still, though, I think their ergonomic designs are quite good and my DD liked using them.