I checked in here without a reservation at 2am and got a twin air-conditioned en suite room for 300 Baht for the night. The room was comfortable and clean, if slightly shabby. The staff were helpful and spoke a little English, enough to get me checked in - unusually, the check in form I was asked to fill in wasn't in both English and Thai, just in Thai, so I do wonder if this hotel is not aimed at Western tourists.
The location is good; Mae Sot isn't huge, but this is pretty central.
For the price I thought the hotel was excellent value. I would certainly stay here again, although I think I would prefer somewhere slightly more expensive but with wi-fi. (To be fair, I didn't ask if they had wi-fi, but there were no suggestively named networks visible when I checked, and I saw no mention of it anywhere.)