This is a great place to stay & the rooms are nice, but it's just missing a couple of small extra touches that would make it a fantastic BnB.
Check-out time is at 12, but they'll keep your things in the little front office for you if you're leaving the town much later in the day. They were also kind enough to allow me to shower before I left Sukhothai, which was way after checkout time & fantastic after cycling around the ruins all day. The owner gave me a towel & there was shower gel in the shower. Totally worth it before getting on a train or a bus for a long trip!

Pros:
Location - it's close to the ruins if you don't mind a 10 minute walk or a short cycle. There are other places closer to the ruins, but they don't seem to be of the same quality & are aimed more at backpackers. Ignore the whiny comments here about it being far from the ruins - it's an easy cycle or you can rent a scooter if you're lazy ;)
Rooms - my room was quite lovely, comfortable, clean & neat, with a nice-sized canopy bed (which took up most of the space) & a large bathroom. In typical Thai style, my towels were styled into 2 swans on the bed, with some decorative flowers. There was a flat screen TV with satellite, mini fridge, hanging rack for clothes, basic cupboard space & a good aircon. Outside the room is a bench where you can sit & read or smoke - though I was in one of the rooms in the double-story section & sitting outside means that your neighbours walk right past you, so not much privacy there.
Service - the service is average to good, depending on what you need or request. Staff are helpful & nice, but I think the language barrier means that staff may come across as unfriendly sometimes, when in fact they are just shy when it comes to speaking English. I had no problems with communication however. Also, staff will organise transportation to the ruins, to New Sukhothai & a tuk-tuk tour of the ruins if you want.
Food - breakfast was a Thai & Western affair with soup, rice, toast, eggs, fruit, juice, tea & coffee. There was no cereal provided, so you'll have to make a request if you're a cereal fan.
Bicycle & scooter rental: you can rent a bicycle from the BnB for 50B a day (20B more expensive than in town) but it's really worth it because their bicycles are in MUCH better condition than the rental places in town (wobbly wheels etc etc), plus you can return the bike when you leave & not by a set time of day. Also, they have bicycles with baskets in the front, which is handy for carting around your lunch & things while you cycle between ruins (never leave anything of value in there unattended & hook your bag onto the handlebar so that it can't be snatched while you peddle).
Value - for 1090B, it's pretty good considering the location, food & quality of the room.

Cons:
Room - the sink in my bathroom leaked, leaving water all over the floor when I used it. When I mentioned it at reception the owner's reaction led me to believe that he was aware of it. It was not fixed during my stay. In addition, the shower drain smelled bad & only lessened after a good rinse & long shower. The bathroom is a bit bare.
Noise - there were renovations going on nearby that are a bit noisy, though not to the point where you can't sleep. These started early in the morning & only stopped quite late at night. There's also a dog nearby which is a bit of a yapper & it goes on a bit sometimes.
After cycling around all day, however, you should be pretty exhausted & falling asleep shouldn't be a problem.
Food - I think that breakfast could have a bit more variety - I think some will struggle with the lack of cereal or something like bacon.
Pool - there is no pool, which could be a problem for some.

I would definitely have rated the place higher if it had better finishing touches:
Shower gel & shampoo are provided in a giant plastic dispenser in the shower - there's just something nicer & classier about little bottles of shower stuff.
No face cloth - which is a handy & nice touch in a BnB.
The bathroom is *really* bare.
There are no tea or coffee-making facilities in the room, which is a pity.

My wife and I loved this place.
We had only planned on staying 2 nights in Sukhothai, but after our first night and seeing the immensity of the historic sites, we decided to stay an additional 2. The fantastic little cottages are clean and quiet with a lot of charm. The owner is really helpful and operates her business with a lot of care and attention to detail. Breakfast was wonderful, as was the laundry service and available scooter rental which we took full advantage of. The main town was only a 5 minute scooter ride away and has a great little market, some shops, restaurants, and of course dozens of ancient ruins can be found everywhere. I'm certain we would have enjoyed this part of Thailand regardless of where we stayed, but Thai Thai Sukhothai definitely made our adventure that much better!

We were quite pleased of this accommodation. The room was not large but comfortable, and the bathroom nice and spacious, if simple. Everything was spotlessly clean and well kept. Wi-fi worked quite well in the room. The staff was very nice and kind, even if the fluency in English could be improved. It was very easy to get a good bicycle to go around, and the main area of the archaeological park are at a short distance. Along the way, you can find some small restaurants who have decent Thai and Western cuisine, and look to the activities of the common people. The place is quiet but not secluded, and we were quite happy there. Coming from and going to the small airport is no problem, but you must count around one hour.