Without more specific info on your preferences and plans, I think the location of the RC (and the Marriott next door) is pretty good for a mainstream tourist visit (unless you're under 30 or so).

The immediate vincity is pretty boring. But many tourist attractions are in walking distance and it's also fairly well-connected by public transport. You'll also have convenient access to supermarkets and off-the-shelf restaurants and shops like Pret or Five Guys. (If you're more into fine dining, the RC is also relatively close to a few Michelin-starred restaurants.)

If you're into high-street shopping, the WA or the IC would be more obvious choices.

Personally, I prefer the IC. The Marriott is also quite good (never been to the RC) but can command quite a price premium. I recommend against the GH, I feel like with many German Hyatts, it could benefit from some upgrades.