Every time I got any issue, I would ask help from them and got resolved really soon. And for this reason I did not move out for years.
Most of the time my website runs stably while I also found sometimes it was stopped without reasonable reasons. I got such situations several times and finally I found after I run some actions causing large disk or network IO, then my VPS would be stopped. One time such thing happened when I was updating my CentOS6 and after I started my VPS on the control panel manually I found my system was broken and could not be booted. I thought 'yum update' command was a general command and of course it would cause large disk and network IO, but it was not my fault and my VPS uses far less disk and network IO than the given limit. I was lucky as I could boot into the emergency mode and fixed the issue then booted it.
Another reason is that HostKVM does not provide DNS PTR lookup and now I want to enable the mail function and this point is really important.
Such moving is just about changing IP address and I could do the cold migration so it was really easy and I upgraded the OS to CentOS7 also.