I stayed at 85 Exeter over a year ago in May 2008. At that time, this B&B wasn't even listed on Tripadvisor, so I couldn't review it after my trip. Now that it's listed, I'll copy what I have written in my trip report:
I called the B&B directly to book. The owner, Susan, answered the phone, and she seemed so nice over the phone that I decided to go ahead with the booking even though I could not find any online reivews anywhere.
The B&B is has 3 floors and she rents out 2 rooms. Mine is the smaller one on (US) 3rd floor. It has a twin bed (plus a roll-out twin underneath). I'd say the room is fine for 1 person, but probably is a bit cramped for 2 if you are someone who likes to hang out in the room. The bathroom is outside the bedroom just next door. It is a private bathroom with full bath.
I also asked to look at the other room, which is a larger double on the (US) 2nd floor. It is very spacious and has its own en-suite bathroom, but shower only.
Location-wise, it is <5 min walk to the Cathedral, 5-10 min walk to center of town, 20 min walk to train station. On the same block, there are 3 other B&Bs (Cathedral View, Cathedral Cottage, and Spire House).
Susan is a gracious host. I felt like I was staying with someone I know. Both guest rooms face the back instead of the front of the house. Downside is one cannot see the cathedral spire; but major upside is how quiet it is. Exeter Street is very busy and I imagine it's noisy facing that street.
I was offered tea and biscuits when I arrived in the afternoon on my first day. The living room is comfortable with plenty of magazines and guidebooks to browse. Susan also has great restaurant suggestions.
Breakfast is laid out each morning on the ground floor room. 3 types of cereal, fresh cut fruit, greek yogurt, OJ, milk. Choice of freshly-brewed coffee or tea. Susan then cooks breakfast to order - choice of eggs, sausages, bacon, tomatoes, mushrooms - any or all of the above. There is also toast, which is homemade by Susan. What a wonderful way to start the day!
Susan is also a docent/guide at the Wilton House, home of the Earl of Pembroke. One of my reason for visiting Salisbury was Wilton House, so staying here with Susan around is almost an extra bonus. She has several guidebooks on Wilton House so I could read up on it before and after my visit. She even gave me a ride home from Wilton House at the end of the day, so I didn't have to wait for the bus.
In summary, this is a great place to stay in Salisbury, and the hospitality offered by Susan made this place extra special.