First, let me say that in my opinion, paying for a waterview room at POR is a huge waste of money. Of the three times I've stayed there, twice I paid for the waterview. First time was a view, through the bushes, of a quiet pool. Nice room but not worth paying extra for. Second time, we were traveling with a family who was used to 'deluxe' accomodations, so I booked a waterview again, but asked for a view of the river. Yep, I could see the river...as long as l left my room, went to the railing, and hung over to see a bit of water through the trees. You have no balcony, so it really doesn't make much difference. For the most part, you will keep your drapes closed since people will be walking back and forth in front of your window. Why pay extra for something you really can't enjoy?
I would opt for a standard view at POR. I love the studios, don't get me wrong. But, for the difference in cost, you'll be getting a slightly larger room, with a kitchenette, rather than a coffee pot and a fridge, and a sofa bed and a queen bed rather than two doubles.
It's a personal choice...just be sure to do your research before you book. Which I guess you would be doing since you asked here..duh!!