What didn't you like about Pristine? That would help in the recommendation of another apple.
Williams' Pride is a good apple with some complex aromatics in its flavor. It has been 2 years since I have one, so it is hard to remember exactly what it is like. It also has a red tinge to the flesh near the skin. Pristine it will mellow in storage, and can store for a while. Pristine is textbook summer-apple sour when you first get it, but last year when I was getting them for a full month from an apple CSA they got better by the end.
I'm a big booster of Zestar, but I guess they only grafted it to G.935, and G.935 is equivalent in size to M7 in my n=1 experiment.