Best location

South Ken is fine, you can get to Westminster in no time at all either walking, by bus or tube (11min on the tube, 40min walk).

Westminster isn't a better location than South Ken, it's just different. but if you can cancel free of charge, make the change, but there is more or less nothing to choose between them.

What did you see, or not see on the maps that concerned you?

Thank you. We have chosen a few key things we want to do while in London (Tower, Tate, and a theater show). While these seem to be closer Westiminster area, I like the neighborhood feel of the place we reserved in So Kensington. We like to walk around in the evening and discover new restaurants and bars.

I would keep the S. Kensington hotel. You are very close to one of my favorite museums in London there, the V&A--Victoria and Albert.
You have good tube and bus connections in S. Kensington, so you can travel easily to anywhere you want.
The Westminster area is a little jam-packed with tourists for my liking.
My personal preference, I would choose S. Ken over Westminster.

What is your hotel you have reserved in S. Kensington?

In my opinion, the hotel itself is just as important as its location. Staying in a hotel that is really great (great service/staff, comfy beds, spotlessly clean) can "make" your vacation. Just as staying in a really bad hotel can come close to ruining your vacation. And by bad, I mean it could be an expensive hotel where the staff simply does not care, gives bad service, and the rooms are not up to par.

If you have found a good hotel, with good ratings on Trip Advisor in S. Ken, stay with it.

I'd stay with South Ken, both areas are great, and many more others not mentioned. You could pick any Zone 1 location and be near loads of great things. And its easy to travel around and light outside until after 10pm in June, so you can enjoy walking between them.

Thanks for the replies. I really want to keep my reservation at the Adria Boutique Hotel, so I am glad to hear So Kensington is good location!

That's a wonderful location. I stayed at the Holiday Inn Kensington Forum (not a whole lot of character but we had our reasons) and the area is very walkable and has great tube/bus connections. That area of London is my preferred because of the transportation options and proximity to Hyde Park and museums.

To the west of your hotel about 5 blocks is Gloucester Road tube station. To the east of your hotel about 5 blocks is the South Kensington tube station.
From both stations you can get on the Circle, District and Piccadilly tube lines.

Using the Circle (yellow line on tube map) or District line (dark green line on the tube map) you can travel east several stops to Westminster tube station, which puts you out at the foot of Big Ben, Parliament, and near Westminster Abbey.
Travel farther east on the Circle or District to the Tower of London.
Using the Piccadilly line (dark blue line on the tube map), you can travel to and from Heathrow Airport.
The Circle line makes a big circle around London.

Using these tube lines, you can get all over London easily.