I have recently done some extensive research on Drupal hosting and have come to the conclusion that Hot Drupal is the best hosting choice for Drupal sites that need substantial resources tuned for Drupal, and where flexible scaling is important. So far, a new client's site hosted with Hot Drupal is doing very well.
Hostmonster is remains a good option for low cost reliable hosting for small websites which are not expected to have heavy traffic.
SiteGround was very disappointing. The entry level plan wouldn't even run one client's application, which has many add-on modules installed.
I am currently hosting my own sites with Drupal Value Hosting, and my sites hosted there perform very well, but there have been security breaches, lost crontabs, and poor support. Therefore when my year is at an end, I will be looking to move my sites to Hot Drupal.