Due to the traffic control policy which seems to be implemented whether or not you are a "heavy user" this product does not seem suitable for anything other than basic web surfing.
What is a little bit annoying is that they do not quantify what level of usage is deemed heavy. From my results monitoring hostlink response times it didn't seem to matter whether I had viewed a single web page or tried to do some online gaming. Speeds seem to be throttled down during peak times as a matter of course.
Customer service centre is very helpful and tried to get to the bottom of the problem. Technical support seemed much more evasive when pressed for an answer.
Looking at the response below from Sky support you will see they are careful not to mention what heavy usage is as far as they are concerned :-
From Sky Technical support:
Thank you for contacting Sky Help Centre regarding the connection issues that you are experiencing at peak times
I have investigated your account and have noticed the broadband package you are currently on is called Broadband Connect .
This package is monitored under our traffic management policy.
Our Traffic Management Policy works to restrict broadband speeds for a minority of heavy web users during peak times (Our network is busiest between 4pm and 11pm on weekdays and all day at the weekend, but can be busy at other times too, depending on regional, national and international demand). This allows the majority of users to enjoy greater speeds.
If we consider that your usage is excessive we may slow down your connection for the rest of the day so that it has less effect on others.
We slow down the speed for applications that use a lot of bandwidth, for example, streaming, peer-to-peer and newsgroups. If you are a very heavy user we may also slow down web activity like browsing, sending emails and video-streaming.
This will result in your findings that certain addresses will have a longer Ping response time resulting in slower connection to certain sites and applications.
I hope this helps with your enquiry.