The new store open on St Mary's Street is Jacobs. I've been in there a few times, mainly to look at their second-hand line-up, which isn't that much. They do say, however, if you have a look on their website and see something you like, they can order it over for you.
Most of what they do is printing and processing, then compact digitals, and then some DSLR products. Not bad, but glad there is a bit more competition in Cardiff.