I agree with buying used, particularly as a first rig.
One reason that hasn't been directly mentioned yet (that I saw) is that very often as a new buyer you don't really know what design features and so forth are important to you, as a lot of this really comes from experience. This means that there's a pretty good chance that your first RV won't be optimal for your needs and wants, and that you'll have a much better idea of what all to look for in a year or two. Selling an RV you bought used is much less of a financial hit than selling one you bought new recently.
Maintenance is required on any RV, and while a used one probably requires a little more maintenance on average, it's not an enormous difference provided things are in good shape. Many maintenance items start from day one.
You might want to think about renting an RV for a week or even just a weekend to get your feet wet.