We used to to call them Pirates4u at work. They'd promise some "bolt on" with the contract but never give any paper work and put it through the system as a standard tariff, so when the punter got their first bill sans magic super special P4U deal they'd ring us in a howling rage... Cue lots of slopey shoulders from all concerned.
Had a contract with both at one point or another, never really any issues, but nothing that would want me to stay with them either.
Two of the most complained about mobile phone stores ever ! They have some wonderful deals, they have some nice shiny phones, but when things go wrong look out. Statutory law means nothing to them, they will hide behind their policy well and will mess you about at every opportunity. If they do replace your phone, it won't work. The replacement will be a battered refurbished one (although statutory law says thats what your entitled to give or take how much you've used/abused it etc) Secondly if you want to buy your phone out right like I did a while ago, Phones 4 U are NOT intersted, they want to sell you the contract that they think is right for you. I told them where to stick it that day, the female sales assistant was not very helpful at all.
Phones4U know this because they got taken to court & fined lots of money for it about a decade ago. Can't find the link to the story, it was specifically one of the Birmingham city centre stores that got pinged for it. More recently, they've been slapped for mis-selling : http://whatconsumer.co.uk/phones4u-misselling/
Recently switched away from O2 after 15 years, and joined T-Mobile through Carphone Warehouse. Got a free Nexus 7 too along with an Xperia, and I'm still paying less each month than I would have if I'd have gone direct to T-Mobile and just got the phone. Very painless so far, both devices arrived within 24 hours factory sealed and number transferred from O2 to T-Mobile within 48 hours. Plus I get an excellent HDSPA service on the new carrier wherever I seem to be, where O2 could barely manage GPRS. Nothing else to report, except that I'm happy with my choice. ^ See?
I'd have to run a few tests for you next time I am with the phone, but in general browsing it feels pretty snappy and I was able to tether it to the Nexus 7 to get Splashtop HD running the other day with no major issues. I have read some of the horror stories on here and elsewhere about limited speeds when not purchased directly but so far that hasn't affected me noticeably. That said anything would have been an improvement over O2's signal where I quite often struggled to get enough speed to even open up the Bit forums unless I was in a town or city with strong 3G!
Crapphonewhorehouse should be burnt to nothing and the ashes dissolved in acid and locked in an umarked vault till the end of eternity. Ive used both and had no problems but the one time I did I was almost sucidal by the end of it. As its been said, any problems and your screwed. CPW take no responsibility if anything goes wrong, in fact the say take it to the network. As everything was handled by cpw the network wants nothing to do with you either (why should they with anything other than an actual network fault?) Top it off they are both very good at catching you up in "legal small print" and "mis selling". For example they can say something has a feature or say a charger was missing or the speaker stops working after one day (thats what happened to me). Because of their "friendly" help you get set up in store, the legal small print (which was never mentioned) says that you basically can't return it. They even refused to fix it saying it wasn't their problem and because they set it up in store I loose the "2week return period for faults". In the end a back street vender fixed it and life went on but I have a burning hatred for that company and dont trust phones4u either. Friend also was promised certain "rewards" for joining like so many minuets but what ever way the employee put it through she only got half the mins and data. When confronted he said it was up to the network to fix or that offer is no longer on so I can't do anything with finally the classic "you can't cancel cause we helped you set it up in store". BBC's Dom also took up a case against them and in the end payed the customer out of his own pocket out of sheer frustration. They will use every trick in the book to lie and wrangle out of every situation even up to the final verdict in court (if they don't manage to delay the case till everyone has passed away). Simply when it works, it works very well, when it doesn't......Just bring a knife with you.