I like both sets. The centenials have a great classic look to them and play great and will last forever.
The aramith have a more modern look to them. I am also pretty certain that they are just a bit heavier ( and a touch bigger), and will roll longer. So if you were to switch to a set of aramiths on the same table, the table will feel like it is playing faster.
I worked in a pool room where we had both sets. We had 9 ft GC's.
The more preferred set was the aramith pro with the measles ball. We used them for all of our tournamnets, and kept them on the money tables.
I got quite used to them and like them very much, but I do not feel it is a huge adjustment to switch between them or anything.
Unless you are gearing up to go on tour, just pick the one you like better. Either would be a great choice for good play.
Jw