I love how, even in a time where I am only interested in a single model of handset which all the major carriers stock, getting a new phone contract is still as much of a pain in the arse as the 90s.

My o2 contract is up in a month with my upgrade date tomorrow. I'm currently paying £46~ which gets me far too many minutes but the joy of unlimited data. This is the key problem.

I have a few choices:

* Stick with o2, get a 'free month' because I can upgrade on month 23. However, they've changed their tariffs and no longer offer unlimited data, simply 500mb/1gb. This month I'm closer to 2gb (no streaming or anything, just lots of use).

Do I have the option of keeping my, annoyingly expensive but doable, contract? Or if I save a few quid and drop down to a 500mb or 1gb, what happens when I hit the cap?

* Vodafone, can save 20% via work but seem to be very vocal about not offering unlimited data. Also haven't had anyone over my new house on Voda so no idea what the signal strength is like. It's a bit of a blackspot for ANY signal but I know o2 doesn't completely drop at least.

* Orange/ T-Mob, been with both before... any reason to consider them again now? Again, not had any feedback on signal.

* Three, worse signal as verified by a friend. So cheap it might not be an issue, and I live in a capital city so outside of my house I presume it'll get OK coverage.

Any option jumping out to anyone? Phone will be an iPhone 4S.

Three is usually a good option for unlimited data, I considered Three... I tried them for a month but found their signal in my house was very very low and in general the signal was rather poor as they are 3G only.

Because of that I decided not to go with Three, so I signed up with Orange as they seemed like the best option and I am very happy with the service... I have a 1GB data allowance. With their merger with T-Mobile not only is their 2G signal excellent, they have 3G just about everywhere (As T-Mobile & Orange merging has created the UKs largest 3G network), so you will have a 1GB max allowance but you will have great 3G (Much better than O2), Or you could just upgrade with O2 and get a 1GB data allowance. So there are 2 options there but if you are going for a 500MB, 750MB, or 1GB allowance go with Orange i'd say (Depending on coverage where you are of course).

As for your O2 unlimited data plan, It may be expensive but if you really NEED unlimited data, keep it! It may be expensive but going over a 1GB cap on another network will be even more expensive, and once you upgrade from that plan you are on you have lost it and can't get it back again.

SO Orange and O2 are good options, Three could be too but really depends on their coverage which isn't always great and their CS is appalling, I can't recommend T-Mobile as they cap 3G speeds to silly things like 1Mb/s, I also can't recommend Vodafone as their standard data plans aren't exactly generous but you could consider it if you like.

There are some options to think about, choose carefully and good luck with your decision.

No O2 won't grandfather your unlimited data if you take out a new contract. Your only option to keep it is to buy the 4S outright and keep your existing contract.

It costs the same overall but you have to be able to afford the entire cost of the phone upfront as a contract phone tariff includes the cost of the device anyway.

ajh - thanks for the feedback on the other carriers. I remember the good old days of Three having o2 as their 2G provider so were able to lock our old NEC phones to that for a good signal! On o2 I get around -100db in the house on 2G, I get the feeling my phone would be hunting for signal a lot and that'd kill the battery.

rich - cheers for confirming what I presumed would be the case. Gone are the days where I was somehow able to keep my 'Everyday 50' contract on Orange for about 5 years despite it being off list for 4 of those.

No probs pHo, and yeah I remember those days... Three was best then cos as well as their great 3G you could get a 2G fallback where their 3G was no good (Like where I live)

I had the same problem as you having been with O2 for 5 years and had unlimited internet - it was a wrench giving it up... but o2 could not get me the phone I wanted at a reasonable price so I jumped ship and went with a 3rd party company

waiting for the best deal I could find was the hardest part but eventually caved in and got a 12 month contract as I hate these longer one's they try to force on us these days

must also put a good word in for Tesco Mobile sim deals
just got my daughter a sim for £12.50 a month with 750 mins 5000 texts and 1 gig of data and she uses my old htc desire

Spoke to o2 yesterday who advised that after you break the 500mb or 1gb cap they simply slow the service down. Given that o2s 3G speed is, frankly, abysmal these days (I get great coverage where I spend most of my days, usually -58db to -63db full bars, and I get <200kbit) I doubt I'll actually notice the difference! So I'll bow down to 500mb and save a few quid...

This is indeed the case, they send you a text message when you reach 80% of your allowance and then just make it pathetically slow when you reach 100%.

I tend to use around 750 Mb a month so had to go for the 1Gb tariff

Actually my brother uses Tesco Mobile and I have to say they are very good, the deals are fantastic!