It is clear that there are serious issues at the moment in Reg365, and as I said before I was willing to put up with some of the intermittant problems that used to happen in the 'old' days, but over the last year I have had nothing but stress from dealing with 365's issues, and getting no help from them in the slightest.
To address one of your points H365, it is true that R365 is the largest but I know that for a lot of my friends who work in the industry, it is sometimes easier to try and put up with the problems rather than having to transfer away from R365. For companies that have a large of amount of clients it is a mammoth task, which could span months.
And ~anyone~ that I have spoken to who is in the know when it comes to hosting, even if they have never used 365, is aware of the sh.it service that is provided.
Being the biggest doesnt always mean being the best! Could it be that they have so many customers that they are thin on the ground when it comes to support? This has certainly been my experience over the last 12 months.