o2 online tariff vs o2 highstreet store tariff, I can't decide

Hi everyone I'm a newbie.

I am on the verge of moving from Pay and Go and on to a contract. But I cannot decide to either go to my high street O2 shop or online to take out my contract.

I know that I would get a slightly better deal if I opted for an online tariff over the high street one. But apart from the deals point of view, what are the advantages of going for a high street tariff (if any).

I have heard that if you get your phone/contract through the highstreet O2 stores you are provided with more help if you need it than you are with online tariffs. Basically if you have an online tariff could the O2 store turn around and say "we cannot help you has you are on an online tariff?" or would I be given the same level of help/customer service no matter if I were an online tariff or a store tariff customer.

I have also heard from a number of people that with online tariffs you basically after to do all the problem solving yourself, dealing with call centres etc, where with highstreet tariffs, the O2 staff do all the problem solving for you. I would really appreciate the help.

Thanks