The experience of visiting the building and climbing to the top floor was wonderful. However, keep in mind that if there's a wedding, the areas you can visit will be limited. Even if you have a designated time like 10:00 AM, it's not really a fixed time. It's essential to print your voucher, as you'll face significant difficulties if you don't. If the weather is good and not too windy, definitely try to go to the top floor. You'll get a 360° panoramic view of London, the best view you can find anywhere. However, if you're a larger person, you might want to reconsider, as the stairs and passageways are extremely narrow, making it impossible to pass by others easily. I barely made it up myself, it was very tight.