We've stayed at dozens of hotels, at different quality levels and prices. This trip was our first trying "serviced apartments" or "apart-hotels" and we got experience at two different properties booked through Hotels.com. Based on that experience we were very happy with the Crawford Suites. Someone had clearly put a lot of thought and effort into renovating the apartment to make it comfortable and functional.
First off, the old windows worked, and a second set of interior sliding windows had been added. All the furniture and cabinetry looked to be Ikea, which is fine. Appliances were in great condition and both air conditioners worked well. Lighting was done nicely. Towels and linens were fine, and the beds were firm but comfortable (even the futon).
Everyone we encountered was friendly and helpful, check-in and out were easy, and the housekeeping staff did a fine job. The neighborhood is on the east edge of Marylebone, a few blocks from Edgeware Road Underground. The building is around the corner from Edgware Road, so generally quiet (our room was on the back side). Local restaurants and stores are mostly middle eastern, plus coffee places, Pret a Manger, etc.
Minor complaints: Carpeting could use a deep cleaning, and the bathroom seemed to be set up for a very tall person (toilet, mirror and bath were rather high). Overall it was on par with a decent hotel room--with the advantage of two sleeping areas and a full kitchen!