My passion in OpenSim is building and content creation. I've tried hosting my own regions and quickly discovered that I don't enjoy the IT end of this little adventure. And I am not very good at it!
Zetamex is not my first hosting company since I moved to OpenSim from SecondLife, but they are the best so far. I chose Zetamex because of a recommendation from Maria Korolov at Hypergrid Business. I have stayed with them because customer service is important to them and they have gone out of their way to resolve any problems I might have in a timely manner.
I understand OpenSim hosting companies have a very tough job. They often do not have any control over the Grid. The OpenSim software is still considered beta and is in a constant state of flux. They have no control over the viewers. And I tend to tax regions to their limit and beyond!
Zetamex does a very good job hosting my 4 regions on OSgrid and my 1 region on Metropolis and worth every penny I pay them!