Personally, I think both Ultra Ball and Pokemon Communication are good cards, both having their advantages and disadvantages. Ultra Ball is pretty good to use when you don't have a Pokemon in your hand, or if you have something to get rid of out of your hand. Pokemon Communication can be rather efficient in that it can get rid of unneeded Pokemon in your hand and exchange for a newer, needed one.
As of now, I think both of these cards will be staples in a lot of decks. The count will most likely be 4 Communication and 3 Ultra Ball. The reason why you run 3 is because if you play 3-4 Junk Arm in your deck as well, you can be discarding quite a large amount of cards. However, only time will tell. Perhaps the count could even increase to 4 just for the sake of easily getting evolved Pokemon (due to the fact that right now, Pokemon Communication is one of the few efficient ways to grab evolved Pokemon)