Back to the original thread question...
There are a lot of things to consider when buying reseller accounts.
The first and formost consideration is "why" do you want a reseller hosting account. There are many reasons, and each one has different requirements that may affect your purchase decisions.
If you are going to host customer websites, then quality and ease of use will probably be your primary concern. But knowing a little about web-servers and data centers will be a plus in making your decisions.
Servers hosted in established data centers usually have better quality and faster connections to the internet backbone than a server hosted from someones basement or from a small company (who will be paying tooo much for their conection to offer competitive prices).
As a note, there is not much difference between the cost of leasing dedicated servers or co-locating servers. In fact, leasing is usually more economical considering software packages and bandwidth, than colocating a few servers. There are different levels of hardware and software support, even with managed dedicated servers. And good quality bandwidth does cost money.
It is also important to note that most data centers provide 1,000GB to 2,000GB of bandwidth per month per dedicated server, and will charge high fees for additional bandwidth. Some data centers will provide unmetered bandwidth but lower prices usually mean lower quality bandwidth. The prices average about $250 - $500 a month for a decent server.
If you are planning to host customers in a shared environment with other resellers then you will need a server suited to that environment. It will require more processing and memory than a small server that only hosts a few hundred basic websites. You will probably want a server with P4 2.4Ghz or better processor and 1GB memory.
A well configured linux server with WHM/CPanel and the works will use about 20GB of space for server use.
Knowing all of this will help you to make a more informed decision.
Avoid under-priced plans or plans that offer to much bandwidth in proportion to webspace space. Both are an overseller strategy and an indication that the company either lacks experience and good judgement, or is just outright scamming. Don't let anyone convince you otherwise.
If someone pays $200 a month for a server with 100GB HD and 1,000 GB BW, and then pays another $50 to $100 (I'll go with $50 here) for server security, management and support...
they will have about 80GB of hosting space available, at a cost of about $3.00 per GB HD, and can offer at the most 12GB of BW per 1GB HD.
These are only averages, but anyone selling plans for under $4 or $5 per GB HD, is most certainly overselling. And be suspicious of plans that offer too much bandwidth for the space.
As far as features go, WHM/CPanel is the most common an easiest to use control panel for hosting. The features included are pretty standard and well supported - custom nameservers, addon domains, subdomains, MySQL databases, stats, scripts, Fantastico, etc.
As far as general problems go, in my experience it has been the same with every hosting company I tried. Servers are always down, spammers are using up all of the CPU and other resources, someone always insist on running some crappy CGI script that crashes the server... and then ultimately, the server is hijacked by someone that had SSH access or the company goes out of business (usually within days after you make your payment).
I lost a few $X,XXX last winter on several different reseller plans, even with popular hosts. I finally just moved to my own dedicated servers. I'm glad I did... now I have a better understanding how the hosting industry works and I can offer my customers better quality and reliabilty... (this is not an ad).