Please understand the maintenance is vital and will mean all servers in the whole of the RapidSwitch data-centre will be powered down.
If you actually read it, you will realise the actual downtime will last from 5 - 8 hours (more likely the former). We have also put plans in now that will further improve this, and have modified the notice to '4 - 8 hours' (this means the service may only be unavailable for 4 hours - which is half of what you've interpreted it to be).
We will be monitoring the maintenance carefully throughout and hope to have everything running as normal as soon as possible after the data-centre maintenance is complete.
Re: "What on earth can they be doing that takes that long"... Unfortunately the data-centre are forcing us into this downtime as they have to conduct essential repairs on their power systems.
RapidSwitch offer excellent data-centre services. We were extremely shocked to hear that they were scheduling such a long period of downtime and are disappointed with them that they have had to arrange this due to their faulty power systems. Unfortunately there is not much more we can do for our clients in this situation than make the downtime as minimal as possible and keep our support systems online and promptly responsive during the maintenance.