Molded fiberglass not only wins on longevity, but it also has a significant advantage in resale value. That can mean thousands of dollars if your needs or plans change along the way.
Other than molded fiberglass construction, the three brands you mentioned- Scamp
, and Oliver- have little in common. Size, price, build quality, and interior design represent very different points on the molded fiberglass spectrum.
Since most do not sell through dealers, one way to get a first-hand look and find out where you fit on the spectrum is to attend a molded fiberglass rally
in your area. In the "more" tab at the top of the website is a link to this year's rally map
. If you missed a 2016 event near you, many of the events are held annually. Contact event coordinators for advice about scheduling a visit.
Olivers are not so common. There your best best is to contact the manufacturer directly. They may be able to set you up with a nearby owner for a demo. Most of the manufacturers offer a similar referral program.