I was met at the airport as agreed and received a room on the Hyatt Gold floor (I am a member). The room is just your typical good size business hotel room. The bathroom, however, is larger and nicer than in many hotels, with black marble, a separate shower, a large soaking tub, and a very fluffy robe. There is a safe and an ironing board, a TV, an ipod docking station, and a mini bar (haven't looked yet).
The lobby, especially the outdoor part, is very scenic and seems like a great place to while away the afternoon (which I hope to do later this week). The spa is very nice (and super affordable - I just had a 90 min African massage, a 30 min scrub+spa tub soak, and bought a jar of product the massage therapist used - all for ZAR 1200 - which is just over EUR 100 I think; I only wish they had fresh fruit and hot tea) and so is the gym - again, larger than in many hotels and well equipped with modern machines.
There is a fantastic looking small outdoor pool which I haven't tried, a steam room, a sauna, and a hot tub.
Overall a great choice and I would not hesitate to recommend. Haven't tried their food, but breakfast selections, which I am looking at now for tomorrow, look good (and cheap!) with plentiful continental, egg, fruit, yogurt, cereal, meat, etc. options.

Johannesburg was my last stop in South Africa and I stayed at this wonderful hotel for four nights with a safari in between. I really have to compliment the staff - everyone was terrific. I decided at the last minute to do a safari and the hotel was able to rejig my reservation allowing me to go to Pilanesberg for three days. The hotel is connected to what seemed like a couple of different malls which was convenient because the Hyatt in a residential neighbourhood. The rooftop pool was beautiful and the gym modern and well equipped. This is an excellent hotel to get work done, or for relaxing.

With these chain hotels, you always look for something different, something special. And there's always a temptation not to like them, to complain that they all look the same. Hyatt, in particular, at the top end does manage to create a certain look and feel. But unlike with some chains, the Hyatt does it so well: it does classy, tasteful and sumptuous.
The Johannesburg Hyatt has huge rooms (and I could see that mine was one of the smaller ones) with acres of carpet, acres of marble, huge TV, huge windows and a bed big enough to graze small horses. Or even medium-sized ones.
The bathrooms are spacious but not on the same scale, with a separate glass shower cabin, although the overall effect was reduced by a remarkably feeble shower head. The water trickled out. Normally in these kinds of hotels the water pressure blasts you into the opposite wall and you have to peel yourself off with a spatula, but this shower was like drizzle.
The public areas were grand, as to be expected, with incredible smiley, helpful, eager staff everywhere. There's a huge gym and a rooftop pool alongside a spa.
The hotel is by the Rosebank Mall, but more importantly it's just 30 seconds walk from the north exit of Rosebank Gautrain station.

This is a world class hotel. Unbelievable service. Staff was polite, eager to serve, and exceptionally friendly. food was delicious. Well worth the price. Pleasant outside patio for Alfresco dining. great location to shopping center and rail transport to and from the airport.