teesom had one shutdown a couple months back that lasted for about 12 hours. That's the only one I am aware of. They have been doing some small tweaks here and there, some of them are more useful than others. Thankfully the shutdown was after east coast business hours on a Friday, so it didn't affect me.
I'd really like to see UPS integration, but the rest of the software is so good that I can't really complain. looing for inventory is 10 times easier with teesom than manually looking.
teesom has unlimited price matrices, which I don't really take enough advantage of to be honest.