If you are coming in the next 5-6 weeks, a busy time, where you stay will depend on where you can find available accommodation.
Tofino has the cachet, is higher end, more expensive. Ucluelet retains its characteristics of the fishing industry. Usually tour companies go out of both locations. They are only about 40 km apart from each other so Ukee, PRNP and Tofino are all of a piece when it comes to touring.
Sorry I forgot to say that we'll be coming in August next year. I've been looking at Airbnb as hotels seem very expensive.
you are not likely to be getting good prices from hotels this early so I would not commit too far ahead. Oct-Nov would be a good time to start looking.
Expensive is relative so giving a budget is always a good idea and in $CAD as that is the currency you will be paying with. Tofino has been discovered so there is nothing "cheap" there in the summer months. You need to go stormwatching in February to get cheaper.
It really does not matter which town you stay in as the drive between the 2 towns is not great and you will travel half way across to the get to the access points in the Park
Expensive is the word for Tofino, Ukee not quite so much.
If you looked and booked next January for accommodation on the west coast, you might find more reasonable prices than you are seeing now for this August. As for short term rentals (AirBnB and other rental vehicles) I think Island TA members would be able to help you there. It's BC Day long weekend here, through Monday, so the forums may not be operating at full force at the mo.
EDIT: You may already know that you will need an eTA to be able to board a flight to Canada. The official website is here. Get that done in good time because some travellers have experienced nail biting waits and some applied too late and lost their trip.