I run a moderately busy website (www.trollitc.com) averaging 55k hits a month (with some spikes of 5-7k hits a day). Prior to this I ran a very busy (250k+ hits a month) site. Until a few months ago I ran it on a shared host but found that wasn't adequate.
After a bit of searching, I came across www.esited.com. I've been using eSited's managed Linux VPS service for over three months now and I'm very impressed.
My site is a wordpress site, which I manage through cPanel. The initial setup went very well and what questions I did have were answered in a matter of minutes via email. With eSited's help I transfered my wordpress site intact from my old, shared host and got it up and running on eSited's VPS in about 2 hours. Once the DNS propagated the site was up and hasn't been down (not even a hiccup) since.
Even on my shared host I experienced non-traffic related outages. When traffic spiked, forget it.
I've been through at least 10 traffic spikes on my current VPS topping out around 7.5k hits in a day (with most of those hits happening over the course of 4 or 5 hours thanks to sites like reddit.com) and performance has been spectacular. No outages!
With my super-cache plugin I don't think my readers even noticed the traffic spike, which is exactly what I'm looking for in a host.
I've got a few years experience running WP sites on virtual Linux servers so when I do have questions, they tend to be a bit esoteric. The help folks are great at ferreting out my issues and helping in getting everything working correctly.
I'd not hesitate in recommending eSited to anyone and in fact have done so twice since they've become my host.