I have a small non-profit forum and have heard great things about KH. I'm currently on site5 (sigh) and I think KH Pro+ or VPS M might suit my needs. I've posted some mySQL usage questions in another topic, but I'm thinking a reseller plan might be suitable for a forum. I'm not actually going to run a business hosting, but I'd like the added features and reliability. I don't need control over every bit of a server, just the normal stuff and most importantly -- uptime. I just hear great things about your VPS -- but not much about your reseller and shared plans. Are they just as reliable?

I would jump on the VPS L, but cost is temporarily an issue. :)
I can't speak for the web hosting packages, although they are all completely managed and monitored just like the VPSes are :) So I assume they're very reliable.

If yours is only a small forum, chances are a reseller package would be better for you - having full access to WHM, and shell access (etc) can be daunting at first.
I can vouch for the Reseller packages, they are great. However the problem with them is if some one else starts consuming too many resources, it can slow down your site, which can happen at times.
I've had a reseller account for a few months, support has been great. The server I'm on was a bit stressed for resources but they seem to have reigned that in. It's been stable for a few weeks now.

Overall KH has been great. I'm still wavering on upgrading to VPS or not. For the most part reseller package is all I need. I do need shell access sometimes but so far support has been nice enough to run a few commands for me.