24/7 Support is a weird one.
If their systems are up and working correctly, then being there to explain how to change the number of emails a user can send from 500 to 2000 a day when the information is in the knowledgebase, isn't necessary.
So really, what you are looking for depends on your experience as a user. If you need handholding and cannot understand a knowledge base and you only do your work out of hours, then a 24/7 Premium Support is more important.
We really ought to answer questions from the user perspective rather than merely thinking, as hosts, because we provide it, surely that's the way to go.
In the 20 years experience, we've had. A "build it, and they'll come" scenario has rarely paid off.
Sometimes the price is the differentiator if money is tight. Other times it's features if you are doing something specific.
Why are we offering the reselling is another point. If we are a developer and charging between £600-1,000 to develop a site and bung in the hosting for a reasonable cost, then the price is not your issue, just reliability, and you won't care how many bells and whistles your host is offering, as you won't be using those features.
I've done it. When we were using an nginx->varnish->apache stack, we've used to swear that that was the way you want to go, until we found that LiteSpeed was faster still and crashed less.
But the original poster shouldn't be asking what's the best reseller package, but "What is the best reseller package to achieve X for under $Y budget," then we can start putting real answers together rather than merely masking our sales pitch as an answer.