If you are planning on rebranding reseller hosting accounts as your own, there are a few things you should take into account when shopping around for a provider:

Support. Without proper support, you'll lose your customers fast. You will need a reseller host that provides 24/7 support, in at least email form. And the response time should be 1 hour or less, at the max.

Avoid "unlimited." Several hosts may try to be competitive by offering "unlimited" space and bandwidth. This is essentially a lie, and you should avoid reseller plans that offer it. The host isn't necessarily bad per se, but as a reseller you need to know just how much space you can offer customers. Also, read the truth about unlimited hosting.

Uptime. Check any company's uptime reports to see how much they are down. A few minutes per month is OK; just keep in mind that your customers are going to come to you when things aren't working.

Price. Honestly, price consideration should be last. As a reseller, it is much much better to pay a little more for a quality host than to have screaming customers at your front door. Put price as the lowest priority.