Personally I am more comfortable to buy online when i was in UK, only reason is the delivery service, their RoyalMail service is much better then...er.. our local one... I have no issue buying watches online in UK except if i buy it outside UK, then the tax will be an issue :p
anywhere, like Andy said, buy the seller and if the price is too expensive and can get locally in store, i will prefer to buy it from the shop instead
Just my opinion!
scott