Palaces

My thoughts are neither of the buildings you mention are castles.

The Tower of London, now that’s a castle.

Agree with above.

Buckingham and Kensington are Palaces not castles.

Windsor is a castle. Tower of London is a castle.

What type of bad reviews for Kensington Palace? .

We had tickets to Buckingham Palace for 9/22 but they were cancelled after Queen Elizabeth passed away. So, we had to choose something else for that time frame so we chose Kensington Palace as a substitute .I thought it was underwhelming and not worth the entrance fee . There are a lot of Queen Victoria's belongings there especially from her childhood. Had we been able to visit Buckingham Palace, we would not have gone to Kensington. The gardens are nothing special either.
We also took a day tour from London which included Windsor Castle, Stonehenge and Bath. We felt we did not have enough time at Windsor Castle as there was too much time spent waiting to enter and this was with a tour group with prepaid tickets. A number of posters in this Forum have posted that one can take the train to Windsor as a day trip and tour it yourself. That's what we plan to do the next time we travel to London.
We also went to the Tower of London which is very worthwhile. We spent the whole day there. Many posters have suggested taking the Yeoman Warder's or Beefeater's Tours but there were too many people in each group which made it hard to hear anything being said and so we left the group.

I've been to both several times. IF Buckingham Palace State Rooms are open when you visit, I'd do that. As mentioned above, Kensington Palace is slightly underwhelming. When I was last there (pre-Covid) there was a lot less furniture in Kensington Palace as opposed to Buckingham Palace.

I'd not say it's "bad"....just not as impressive as you'd want it to be.On my first visit years ago the best thing was a huge exhibit of Diana's dresses.

How many days will you have in London? I'd say Windsor Castle is also more interesting than Kensington Palace. I liked the small palace at Kew Gardens which is a quick visit when you are seeing the gardens but would not be something you'd do on your own. IF you have time for Hampton Court Palace...well, that tops Buckingham Palace to me. Big, historical (especially the kitchens!), gardens, grape vines, maze, it's got everything, lol.

I’ve been to Kensington Palace twice and neither time was I impressed. I went for the 2nd time last October because of a specific exhibition, which was well done, but I wouldn’t have gone a second time otherwise.

Buckingham Palace is definitely worth seeing if you are there when it is open.

My personal favourite is Hampton Court. Lots to see there and well worth the trip.

Buckingham Palace, being the official residence of the King, and where most of the official events and receptions are held, is the more impressive of the 2, by a royal mile. Kensington houses the offices and London apartments of a few of the Royals, including the Prince and Princess of Wales. But consider that no reigning monarch has lived at Kensington Palace since George II.

I was unimpressed with Kensington Palace. One only gets to see a few rooms that were sparsely furnished. The only redeeming feature was a temporary exhibit of Princess Diana dresses. It’s no longer there.

Skip Kennsington Palace - unless it happens that there is a special exhibit you are interested in. I am not going to check the website. I agree with everything you've heard. I avoided it for years, but finally succumbed in 2022 and am still kicking myself for wasting my money and time and running into two rude employees in the cafe and security. (I have never had that happen any where else - I am certain it wasn't me causing offense.)

Buckingham Palace was a treat for me. Fun to see the rooms that are so often photographed or appear on TV. Crowd control is good - with the timed entry, no huge crowds although it was "full". Quite an art collection!

Other possibilities for you - Hampton Court, Tower of London and Windsor Castle -all as mentioned above. All beat Kennsington Palace by a long shot!!