Amazing hotel. Stayed with my wife in April 2014 on our honeymoon. Very friendly staff, clean rooms. The rooms have hair dryers, safes, and Type M plug outlets (South African standard). The pool is nice and the sunlight hits it just right. I would recommend getting the breakfast option, because their breakfasts are awesome, and they usually last until 11AM.
Top four perks about The Cullinan:
1) Very knowledgeable concierge and staff - they know A LOT about Cape Town and South Africa in general. Even better, they give helpful recommendations from a tourist's perspective (safe ATMs, sightseeing tips, etc.)
2) Free shuttle every 30 minutes to the V&A Waterfront. We definitely utilized this!
3) They know a lot of drivers in Cape Town. We had a free day, and asked for suggestions about getting around town. Within ten minutes, they gave me a cab driver's offer to tour the city for the ENTIRE day (and it was a GREAT offer)! The driver was Jonathan (Phone: +27 847806791), who was fantastic. He took us to many cool places around the city, taking memorable pictures along the way. He seems to have a longstanding relationship with The Cullinan. Ask for him!
4) Close location to Long Street - The Cullinan is close to many restaurants on Long Street.