The Hampton Inn is brand new and very nice, but it's also very much a Hampton Inn. If you don't look out the window, it's totally indistinguishable from any other recently renovated Hampton Inn anywhere (though the views are lovely if you do). There is a pool and hot tub but both are the typical small Hampton Inn size. Everything was clean and well kept (though it had only been open a few months when we visited).
I'd stay there again if there was no price premium, or if I really wanted the points for some reason, but it's not a hotel I'd go out of my way to visit.
BTW, the Hampton is on an Island Explorer stop, so it's fairly easy to get into and out of downtown Bar Harbor (and transfer to the other Island Explorer buses) without driving yourself, finding parking, etc if that is a factor for you.
Location is totally down to personal preference and what you want to do. My personal preference is to stay close (walking distance) to downtown Bar Harbor so I can walk to/from town for meals/drinks/whatever. I figure I'm going to have to drive to most other things anyway (Acadia, etc) so I might as well be walking distance to town.
My personal favorite hotel in Bar Harbor is the Quality Inn on Kebo St. Obviously being a Quality Inn it's a fairly no frills property, but I've found it to be clean, comfortable and reasonably priced. I consider the location to be unbeatable - it's only five minutes walk from the heart of downtown Bar Harbor, and right on the junction of ME3 and ME233, perhaps ten minutes drive from the Eagle Lake Rd entrance to Acadia. Just avoid the (paid) breakfast they offer in the cafe across the street - it's unremarkable at best and they charge just as much as better restaurants in town.