I have stayed at:
Apartments:
* Apartamento Alvaro Jesus. They have furnished apartments and kitchens.
Hotels (in order of preference, all very affordable):
* Hotel Dos Mundos
* Hotel Versailles
* Hotel Costa Linda
- same ownership/managment as Hotel Versailles and right around the corner
* Hotel Exito - only downside is street noise if you have a room close to the street
* Hotel Majestic - probably would have been ok if I had brought a mosquito net
NOTE: I did develop a skin fungus at either Versailles or Costa Linda (don't remember which for sure), but I stayed at both places multiple times prior to that. They are nice and affordable but, frankly, that one experience tainted me and makes me reluctant at this point.
Also, as I'm sure you are aware, where you stay may be somewhat dictated by the proximity of the girl(s) you are visiting.
Hope this helps. Buena Suerte!