Been with O2 for years and do have a good deal with O2 but for internet use is now outdated.
So on O2 I have for £13.99 month. 800mins, unlimited landlines call free bolt on (so these dont use mins). daily web addon (this was up until earlier this year effectively unlimited internet for £1 a day., the £1 a day isnt charged when dont use it, the £1 a day is a max charge if you used 150mB or more that day).
O2 started enforcing throttling of speeds earlier this year after 150mB, that was already in the t&c's they could do that but they never did it in previous years, they just let things slide. As always in most cases when isp's throttle its all but been cutoff, everything is unusable except pings.
Earlier in the year also O2 had their own unlimited package (but not sure if allowed tethering), this is now gone. I almost moved to that package but opted to stay where I was.
Given O2s financial situation and does appear they not investing in capacity to match internet growth, as my dsl was down 2 days ago, I realised I want something better 3G side, as after I watched one single 240p youtube video I was effectively cutoff until midnight. I have now ordered a 1 month dongle with three, when I used to use their dongle in my laptop speeds were extremely dire, I am hoping it was an issue with the dongle and the sim will perform better, so will be testing it in my S2 phone. If it works ok, then my plan is to port my O2 number to three and use the same plan but the 12 month version.
The plan has 2000 mins which I hope is enough to make up for the loss of unlimited landline calls, 2000 text which to me is odd as usually everything is unlimited text now days, but i cant see myself using up 2000 so is ok.
I ordered the normal sim since its been used in my S2 initially and then will move to my S3 if I ditch O2, I wish now tho I just ordered the mini from the start used ti with adaptor in S2 and then easy to put i S3, as three are saying if I switch to the 12 months I wont get a new sim, they expect me to take it to a shop for it to be cut, seems cant just order blank/new sims from them like on O2.
Others are generally happy with three? signal reliability and 3G speeds?