I too read some of the negative comments on the net about Mosso but i thought it was worth a punt. At the time there was the 50% off and a 14 day trial. I did the trial and have not looked back.
I have to say that Mosso have the best technical support I have ever experienced with a host. The 'Live Help' is just brilliant.
I havent ever experienced any downtime either... I have been using Mosso for about two months now.
with my past hosts I have always had problems with one thing or another - email, slow responses etc etc.... never had anything with Mosso.
I am now in the process of closing down my three dedicated servers and moving everything over to Mosso. Already on one of my more busy websites, the load times have been much quicker than with my dedicated server.
Cost wise, brilliant. I think more Compute Cycles a month would be nice though!
One negative, I am not sure about the new Beta control panel yet... maybe i just need to get used to it!
Anyway, if anyone is reading this, dont beleive the old out of date posts about Mosso, they are fantastic!