another consideration is portability - the egg is very heavy & clumsy & can shatter if dropped or tipped over, so for the most part if you plan on keeping it in one spot it's fine but if you want to go mobile (even across the patio) be very careful, I've seen more than enough broken eggs over the years. I have two large eggs that don't move so it's not an issue, my Kettle moves all over the place including out by the bonfire pit to be closer to the action.
Both of the cookers you are considering are excellent and you'll be happy with both, I think it really comes down to what you're looking to accomplish with them. If it's primarily bbq, I'd go with the Weber for many of the reasons already cited. If you want to incorporate scorching high temps for baking bread & pizza and so forth in addition to bbq, I'd go with ceramic, or a keg or other similar style cooker.
Eggs & Kettles