If you know about any other reseller plans I would be happy to hear about it.
We've been using http://olm.net/
for about 4 years and also have a RSE with them. Their reliability has been excellent, but they tend to be a bit behind the industry in keeping up with features (control panel, scripts, add-ons). It's a trade-off (reliability vs. features) that has worked for us so far.
Their support system for resold accounts has pros and cons. The RSE is a pretty good value, but documentation is lacking, though we've been informed that this is being addressed.
(George, I know you read this stuff!! Start cracking the whip!)
Hope this helps