I have had dedicated servers with LiquidWeb for years. They have fairly quick support and great uptime. I did like that I could contact them by phone in an emergency.
I have only a limited experience with slhost (about 2 weeks). In this short time, the server has always been up. I have submitted about 6 tickets at different times of the day. Most were very simple issues that I could have done myself. But I wanted to test the support. All were answered quickly. I was impressed with the quality of the replies. So far I am very impressed with them.