I like my HD box and I think its well worth the cost.
BBC HD - by far the best quality output, Planet earth looks amazing, top gear special looked great, and for some reason even Heros looked better than any SkyOneHD program. Their football coverage is "variable" but it looks good still just sometimes skys looks better. Biggest problem is there isnt enough of it but i usually use it as a demo for the unbelievers. They have even started showing the odd film which is a plus.
SkyOneHD - ok so allot of it isnt actually HD, and allot of it is repeated 50 times a week. BUT 24, Lost (if you can still stand it), Nip/tuck, law & order even some of the newer malcom in the middle episodes. lets be honest they have some of the best mass market american tv shows and if that floats your boat you cant go wrong.
SKY Sports 1&2 HD - Football looks great, so did some of the golf and rugby. I turned it off over the summer to have the movies instead because i wasnt that bothered with copa d'america and i hate cricket. reminds me i need to switch it back on before the charity sheild.
Sky Movies HD 1&2 - again the quality really shows here, some of the older films really suprise (the fly, independace day and ghostbusters 2 all looked really good). Only wish there was more as with all the movies channels they show the same films over and over.
SkyArtsHD - Id like to pretend im all posh and watch this but im not, opera dont float my boat. but that said ive seen a couple of things on here that ive watched in flicking.
DiscoveryHD/NAT GeographicHD/HistoryHD - All the programs look amazing HD really works well for documentarys that show you parts of the world you will never see. The footage from the ISS was truely jaw dropping. As i like this kinda TV its often one of my first points of call if im "flicking" and there is often something worth watching. Again repeats can be annoying but this is par for the course on any sky channel.
Rumoured new channels include: MTV HD, FX HD, LIVING HD, Disney Channel HD but thats been said for some time and nothing has been confirmed.
Overall I think its worth the £10 i really do, the box if you can get it for £150 then yes deffo, I paid full price and my only complaint i like my TV its cheaper now than when i paid for it, but such is life. As with all the sky/freeview channels there is allot of repeats but the gems are worth looking for.