I've owned an ATAS100 antenna for almost 20 years now. I've made many thousands of contacts with it driving across the US mounted to various cars I've owned. All with the same Icom 706 I got at the same time as the antenna.
They're arguably one of the worst antennas you can have. Their nickname "rain gauge" is accurate - water intrusion is a given. Mine has had every possible electrical and mechanical problem these antennas are known for. Performance is on par with hamsticks, but at 20x the cost. It's so bad that I actually enjoy using it. Sorta like fishing without a worm on the hook. Anyone can catch fish with a worm, but a bare hook is a challenge. When you make contacts with an ATAS antenna it's in spite of, not due to your antenna.
On an RV there are zero reasons to run an ATAS. For the same money you can buy a much better solution, which will be pretty much anything other than an ATAS.