I just came back from a semester abroad at Edinburgh, and I lived in Pollock. Pollock halls are definitely nice in regards to its location being quite close to Summerhall. However, you should remember that for the most part, those halls will be filled with 18 year old, first year undergrads. So, if you're not up for that traditional dorm experience, I would avoid Pollock.
On the other hand, there are tonsss of people around for you to meet if you live in Pollock. Of course, most of them will be 1st year undergrads, so I don't know how much it'll help with meeting vet students. Also, you should think about whether or not you would like to cook your own meals. I'm not positive, but i'm pretty sure that everyone in Pollock is on a mandatory meal plan.
Hope this helps, i'd be happy to answer any more questions.
PS: Edinburgh is AMAZING. I spent sooo much time just roaming the royal mile because its so beautiful. Also, walk along Princes Street- the views are incredible.