We visited the Mount Nelson recently (December 2010 & February 2011) & have stayed here several times in the past 10 years.
The guests are a mixture of: Young famlies, Media types, quite old & very old..basically a real mixture, great breakfast, Buffet Lunch & a great garden with shade & a large pool, staff are gorgeous (a little obsequious, but aren't most 4* & 5* Hotels?) Large rooms, with so so wifi & generally great showers.
Kloof Street (out the back of the Hotel) is great for 'quick eats' & shops & seems pretty safe to walk about there day or night. A bit further down Kloof St (walking N E) is Long St, good bars & a great Burger/bar eatery they even do a Vegan Burger :-)! another place to eat & or drink is Dunkley St Square (between wandel St & Barnett St) it's short walk out the front of the Hotel, more a place for a coffee & snack.
If you really want to go to Cape Town then March, April & May seem to be the months that the dreaded wind is all but gone, enjoy.More