From personal experience, i would avoid Sharp. I had a sharp tv, video player, dvd player, etc (yep long time ago) and the tv went kaput almost as soon as the guarantee was up, the video player and dvd still works i think.
Samsung customer support is crap, my bedroom tv is samsung but when the HDMI sockets stopped working (after only a few uses, they wouldn't do anything about it despite having a 5 year guarantee) but if you are in the UK then you should probably check out AO online or even John Lewis as they provide 5 year guarantees on most tv's. I don't know much about Hisense but they are a pretty big brand in Europe and like most electronics companies these days, they manufacture all sorts from washing machines to tv's , i have seen the picture quality and it looks good. I think if your funds allowed, then i would stick to someone like Sony or Panasonic who IMO make quality products.
In the time it's taken me write this, you will have already purchased a tv no doubt but that's my tuppence worth anyway.