I recently stayed at the Mantra on Hay and was impressed. The renovations others have made reference too appear to have been finished and the hotel is better for them. Having stayed at this hotel several times over the past 5 years it certainly benefited from the refit.
The room I had was large, modern and well laid out, especially when compared to the Mantra on Murray which I recently stayed at. Also on the upside there is parking available on site at this Mantra unlike the other one. The staff were also noticeably better than the sister hotel, they were prompt and professional from the front desk to room service. The only grumble to report was the crappy iron & ironing board available in the room, as a business traveler it's always annoying when you can't iron a shirt properly because of a crap iron.
The only thing I'd point out is that it is the quieter end of the CBD so at night you won't find many options within walking distance for a decent meal. During the day it's less of an issue because there's a couple of cafe close by which are open during business hours.More