If you've researched the archives of previous threads, you'll find no shortage of answers. My two cents, for what it's worth is:
The first issue you need to consider when asking this question is your level of experience and knowledge of the industry. If you're just starting out or are still learning the ropes, you're better off driving for an owner or buying something you can pay in cash, while having a month or so in reserve for living expenses.
Another consideration is the pros and cons of a straight vs. a van. The advantage with Vans is they are less expensive to own and maintain and an easy way into the business. However, because of these advantages, there is a glut of vans in the pipe line, meaning stiff competition for freight. The inverse is true for Straight trucks. They might be costlier to own and maintain but the potential revenue stream is far greater.