I visited Sizewell A for a tour as a young teenager, though I don't remember much about it beyond walking over the top of the reactor, and getting an educational comic booklet about how nuclear power worked. I think this was when they were going through the planning process to build Sizewell B, so they were probably in a "community outreach and PR" phase.

You can see both from a way along the coast; personally I think they add to the landscape rather than detract. The sea is also apparently noticeably warmer in the immediate vicinity due to the cooling outflow.