We've stayed at the St marks Hotel twice now, ones I. April 2012 and one in April 2010. It's in an excellent location on the junction of St Marks Place and 14th Street. There are several subway stops within a couple of blocks.
St Marks is close to parts of the university campus, so the area is young and buzzy with lots of cheap (but good) restaurants, bars, yoga studios and tattoo parlours. It's super easy to get around the city from here, you can get to Times Square/Port Authority in about 5 minutes by cab (depending on traffic) or in about 10 minutes on the subway.
The hotel itself is extremely basic. There's a bed, and a couple of bits of furniture and that's it. The rooms are small, but kept very clean. Both times we've stayed we had issues with the water temperature in the shower, it would fluctuate between very hot and very cold apparently for no reason. That being said, this particular problem seemed much improved on our second stay, but that may be because we were on the top floor, whereas we were on the 1st floor during our initial stay.
The first time we stayed our room over looked the street and was extremely noisy from he traffic. The second time we were on the top floor (there's no elevator FYI, that was fun with our suitcases) the room faced out over rooftops, so street noise wasn't so much of an issue, but our radiator made a lot of noise during the night and as the room was high up, it got a lot of sun through the window making it quite warm and the AC didn't seem to work. Luckily it was only April so this was bearable, so we didn't bother reporting it. Other than that, the bed was comfortable, the TV worked and it was clean.
In short, this is a brilliant base in a buzzy, fun, vibrant area, if you're not fussy and just wanting a place to sleep, shower and go. You cannot beat the value for money in terms of location and the staff are fine (but they definitely don't thrive to provide excellent customer service). However, if you want luxury, space, peace and quiet or high levels of customer care, I would recommend a different place. I would definitely stay again due to the location and value alone and the pizza from the restaurant below is awesome, especially if you're returning from a late night.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.