To clarify a bit on the m-10 error, that error is specifically a connection error to our servers. The issue lies in when only a select few start getting M-10 errors. If its happening to every 10 people out of 100, it tells me something may be wrong with those 10 internet connections not properly connecting with our servers. If its 99 out of 100 getting it, it tells me our servers are where the issue lies. As with all games on PS3, it all depends on the speed of your connection (wired/wireless), if and what brand of router you're using, and who your provider is. Sometimes routers set up too many firewalls automatically which prevents Home from accessing your PS3 and will dish out those M-10s often. Other times slight hiccups in a connection due to it being used by other sources such as PC's or laptop's will cause the M-10. If our servers are going haywire, you'll also see M-10.
To reiterate what I've said before, just because your internet is at "full capacity" or it is "working fine" for other PS3 games or even your PC, it does not mean it will work for Home the same efficient way. Home accesses specific ports of the PS3 which have been outlined in the Connection Issue, IPs, Troubleshooting thread. I'm going to be honest here, Home can sometimes require quite a bit of network dedication and can be a bit temperamental when it doesn't get enough. Its unfortunate but that's how Home is designed. In order to deliver a full experience it requires a good solid connection.
I hope this answered at least part of your questions.