I wonder whether it pays off to sell reseller packages. With reseller packages doesn`t it happen often that the customers do only stay with you for as long as they can't afford a dedicated server ?? Especially don`t you create more competition this way ??? I mean by offering reseller packages you actually make it easier for new companies to start... Companies that can be your competition later.
Also it is hard to administrate because they can add lots of accounts to your server and you can't control that anymore etc. for example you can not move one of their domains to another server because they are all in the same reseller accounts...

What do you think ?

I think reseller packages can be worthwhile.

Remember, companies who are purchasing reseller hosting from you are not competition. just remember to set strict space and bandwidth limits.
As they grow with more customers, they will upgrade to a more profitable plan from you, bringing you more money.

Of course, the best reseller customers are the struggling hosting companies that pay for the server but don't get any customers- which describes a lot of companies who purchase reseller hosting fairly well.