My boyfriend and I stayed at Summit Lodge & Spa for one night in September. We found the hotel through a Groupon.com deal. The front desk staff was informative and really friendly; while check-in wasn't until 4pm, she had our room prepared early so we were able to check in when we arrived at 1pm.
Our room was lovely. Unfortunately there was a large stain on one of the chairs, as well as on one of our towels, but other than that everything was clean, tidy and well kept. Comfy beds and extra comfy pillows, mini fridge and kitchen a plus.
The spa/pool area was small but also very clean and very relaxing. Loved the dry sauna, as well as the couches and chairs that surrounded the pool.
While we did not bring a dog with us, the dog-friendly aspect of the hotel was great! It was cute to see them in the lobby and halls, and amazingly I only heard one particularly baritone dog voice the entire time I was there (I'm assuming the walls must be pretty thick!). No barking all night long, like I was kind of worried might happen.
All in all the hotel was wonderful, the price couldn't have been better (thank you, Groupon!), and should we come back to Whistler this season we'll definitely consider Summit.