Hi Botty,
Billyboy is right, it is a mixed bag. I stayed there for 3 weeks once and had a lovely time but it was a privately owned apartment that was only rented out by the owners, not given to a holiday company, so it was nice.
Kitchen area is a bit small with no cupboard storage but otherwise ok.
Santa Maria itself is kept well, reasonable pool, 24 hour reception, lovely help yourself salad buffet at the pool bar thats so good we still call in for it whenever we are in Tenerife. The pool bar also do a take away service.
Didnt eat in the main restaurant but other people said it was fine.
If you ask for 2nd or 3rd floor, at minimum, preferably overlooking pool area (rather than the street) you shouldnt have any problem with noise at night.
The aparthotel is part of the hotel group that includes Club Atlantis, Panorama, Los Geranios and La Nina so they should know what they are doing.
It is in a very convenient spot so if your room isnt good enough have a tantrum!