Markp:
Sorry about your bad experience. I have a site I have been upgrading, starting with 3.x, a couple of 4.x versions, and now is at 4.7 and it is working great. It is running on my own server though, which has two CPUs, 2GB of Ram, but it is kind of old so the CPUs are not super fast. The line out is not super fast either.
Now, if you are talking about initial loading time, this has been documented ad-nauseum. Nothing you can do but to use some way of keeping the site alive.
On the other hand, if you are talking about general performance of the site after it has been loaded, I don't think that 4.7 is inherently slower than previous versions. There must be something going on with the configuration of your DNN installation or the infrastructure in Webhosting4life. It could even be a bad coincidence, they may be having other problems.
Do you have a dedicated server or shared? Have you checked how many other sites are running on your server? If you want to check for other sites, I'd recommend http://whois.domaintools.com/. Enter your site's URL, and then on the result page search for "Reverse IP".
One more thing, can you post more specific details about what happened during the upgrade that crashed the site?
Edit: forgot to mention that I remember reading that this site was (is) experiencing some problems that I don't think were caused by DNN, I forgot what it was now, you may want to do a search.
Carlos