Sky are rolling out new security measures all the servers your f5/f3 would use could go off at any moment, no one really seems to know for definite though. But lots of ads selling servers and very cheap fees for 12 months tell me they are trying to rake in cash quickly. You could buy one and it could work for years or it could go off next week.
On top of that the skyboxes are pretty bad don't get me wrong they work but the interface and epg are lacking, your looking at atleast a couple of hundred for something reasonable