For those with a bit of cash to blow the Melrose Hotel is well worth a stay. The Decor is extremely funky (modern african) and the rooms are beautifully finished. The Hotel is centrally located in the North of JHB with all major highways, shopping districts etc. conveniently close. The Hotel is also situated in a new development (Melrose Arch) with a gallery, restaurants, banks and gym
I've stayed several times at the Melrose Arch and like it pretty well. The rooms are very comfortable (watch out for that giant dish of peanut M&Ms, you may eat too many!) and the place is very modern and hip. As with most hotels in South Africa, service quality is not in line with the prices or the quality of the rooms, but at least the Melrose Arch isn't as appalling as the Michelangelo on that front.
There is no fitness center at this hotel. You have to pay for a voucher to use the Virgin Active gym around the corner, which I must say is absolutely amazing.
The Melrose Arch is located in a small shopping/business park in the northern Jo'burg suburbs. There are a bunch of good restaurants located right outside the hotel, so you don't have to get a cab if you want a nice meal. There's even a very fine wine shop around the corner, very useful for bulking up your SA wine inventory!