Sky don't have the best reputation when it comes to issue resolution. I was a former Sky broadband customer and found their customer care and technical teams to be woefully lacking. Additionally, they have no real SLA to speak of, and all of their service plans (as far as I understand) have a standard 1:50 contention ratio. Ouch. And when I was a customer (a couple of years ago), they refused to divulge the the ADSL (PPPoA) RADIUS credentials, making it much more difficult to use your own ADSL router.

For many users (especially your average home/family users with less technical requirements, not using it for critical purposes such as home working) they're probably perfectly adequate.

FWIW, I use BT's (formerly British Telecom) FTTC Infinity for Business product. 78Mbps down, 20Mbps up, worst case 1:20 contention, no caps or allowance-related FUP. Their customer care and technical teams are pretty decent. And I can get a /29 in addition to the dynamic PPP IP for the WAN link. Where I am (NE Scotland), BT own all of the widely available (non-private) infrastructure so it's easier to deal with a single company in the event of a failure vs being pushed between ISP and infrastructure provider. YMMV.

EDIT: FYI I pay £45 ex VAT (~AUD 102).