I've been with ThisWebHost since early 2010 (mid March) and my experience with them has been unusually pleasant. Before them I was with IX-Hosting (now defunct, probably not the popular one some of you knew about - this was just a re-branded reseller), HostGator and a few nameless others.
Google Checkout took a while to process my payment (it never ended up doing so) so I tried PayPal which unfortunately messed up my first invoice. The support operator seemed a little ticked off, though I could understand why. I ended up going with PayPal in the end.
I originally had two Starter/Blog accounts with them: one for my own blog and one for an organization I was providing IT services for, which was unfortunately disbanded due to inactivity.
I upgraded my account, a few months later (mid August), to a higher plan (Standard) to enable WHM and opened a support ticket asking for an account migration. I ended up dealing with it myself by backing everything up and terminating the secondary account I had with them to move it to a child account under WHM. I had to open a support ticket with them after that due to some inaccurate advertised-vs-actual limits to which they quickly replied and resolved.
I suppose due to increasing customer activity they upgraded to LiteSpeed Web Server to take advantage of the higher performance with Apache compatability. Occassional kernel-update reboots happened back then, and I always got early notice if there was going to be a moment of downtime (except for one time when they had to address a security issue, they rebooted on the same day after sending the email out, understandable). They recently notified me that they have switched to a reboot-less system (not that it was an issue for me before) - that's thinking for the customer.
They are certainly willing to spend an extra buck for the features of these two additional perks, and I couldn't be happier. I have a few VPS boxes across North America, but refuse to move my website to them simply out of fear that I could not match their reliability.
If anyone else here has an account with them, please share your story.
Edit: My domain hosted with ThisWebHost is "bestic.me", moderator please verify.