Samsung, by far.
My Galaxy Note 2 developed a fault, I rang Samsung, they advised I take it to my local repair centre which I did. They told me there it should take around a week to repair, they would be shipping it to another repair centre to carry out the repair and they will call me once it's back.
1 week later - I hadn't heard back from them so thought I'd ring them for an update. The phone was still sat at the repair centre waiting to be shipped to the other repair centre, it hadn't actually moved.
2 weeks later - I rang them again, they said the phone is currently being repaired.
3 weeks later - I have rang Samsung several times by this point really kicking off at the length of time it's taking to get my phone fixed, and because of the lack of updates. Every time I was told I will get a call back, I never did. Anyway, at around the 3 week point I get a call from them saying come collect it, it's been fixed. I go to the repair centre to find it has been fixed, but now has a dent in it. I refuse to accept it back, they say it has to go back once again to the repair centre who repaired it.
4 weeks later - I've complained several times as I'm still without a phone, they don't give two hoots. They fob you off, their CS dept is a complete joke. One of their advisors, a bimbo called Jordan actually said 'we don't normally repair phones with physical damage' as though I should be grateful they are fixing the dent which they put in my phone.
5 weeks later - I get a message saying my phones repaired. I go to collect it to find the exact same dent is still there. I have absolutely no idea what they had been repairing. The guy at the repair centre advised me not to send it back to them again and put a note on the receipt that he had seen it and confirmed the dent was still there. I left with the phone and again contacted Samsung. I managed to get through to someone via an email link on their site who after 5 weeks, arranged for a replacement handset to be sent out. I tell him I've been without a phone for 5 weeks so I will not be sending mine anywhere until I first receive the replacement.
6 weeks later - Parcel arrives for me from Samsung. It turns out to be the wrong phone in the wrong colour, with someone elses name and address on one side of the parcel, and my details on the other. You couldn't make this up.
7 weeks later - Courier arrives to collect the wrong handset, and delivers me a parcel. Finally, the correct phone arrives, which I promptly put on sale and sell. Samsung meanwhile continue to email me trying to arrange collection of my damaged handset which still works fine but has a dent in it. I am ignoring their emails and giving them a taste of their own medicine. The last email I received from them a few days ago said the matter has now been passed on to their legal team lol.
**** you Samsung. I will return the handset once you have waited the same length of time that I was made to wait and no sooner. Understand?