I have a Webmaster SE with them and have been there for only six weeks. I was looking for a VPS and after looking at many different hosts, I decided to give them a try.
Sales people could be better trained, especially for those who are interested in hosting plans that are a step above shared hosting. I have not had to deal with the billing department.
Performance has been very good, as has tech support. One of the reasons I went with OLM is because they do have toll free tech support- I like to pick up the phone and talk live to a real person. They have been good about answering my newbie questons regarding the server, control panel etc.
They could use better online documentation, FAQs and a forum would be nice.