Resin kits have generally been products of small production runs only because the kit being made is usually not a "popular" subject, or is a derivative of something already on the market. Resin is used because it can easily be poured, whereas injection molding of plastic kits is a far more difficult process necessitating much more investment in the proper equipment. As a result, many resin kits are expensive, because they're "niche" subjects.
Having said that, resin kits are not easy, nor for beginners. What's more, they often don't contain "all the parts". A lot of times, you have to fashion smaller parts out of plastic, wire, etc. Cleanup on them is messy and dangerous--you MUST wear breathing protection. And warped kit pieces is always a common problem.
I've been building for 25+ years and only recently got my first full resin kit--a Country Squire Station Wagon. I bought it out of frustration that it's not available as a plastic kit. Surprisingly, it's an amazingly well-made kit, with "all the parts"! I can't tell you what plane models might catch your fancy, but make sure you know what you're getting so that your first experience with a full kit isn't a grave disappointment.