Thought I'd tackle the Kent v Sussex thing here, but appreciate you aren't specifically comparing the 2 in your post above.
I'll see your list with Crawley, Bognor, Selsey, Lancing, Peacehaven and Newhaven and raise you Crowborough and Horley (Sussex town from 72-74).
Lived in Sussex for 30 years and Kent for last 10. On countryside and picture postcard villages the Garden of England wins I'm afraid. And to Canterbury and Whitstable I would add Tunbridge Wells, Sandwich and Broadstairs!
Take off those Sussex tinted specs people!
Newhaven The town centre and industrial estates yes, but the surrounding countryside is nice.
Peacehaven, look either side of the housing, the coastline is nice and the countryside at the top of Peacehaven is stunning.