So is there any time shares where you get good benefits buying on the secondary market or just plan on spending the money and booking through RCI?
They are 2 separate systems, in essentially completely separate parts of the country. And as someone else said, Wyndham doesn't OWN Worldmark, they manage the Worldmark resorts.
Worldmark is mostly West coast and Wyndham is mostly East coast. With some crossover and dual-tennancy locations.
You can't book cross platform using resale points. I'm not sure where the comment about RCI is coming from, but there's legitmate reasons to own both systems. You will learn this the more you research or if you buy one system only.
I'm currently a Wyndham only owner but am about to buy somewhere between 16-20,000 Worldmark credits because I see value in having both. Gives me a lot more flexibility on the West coast, and even though I have (some) retail points and can use club pass, the fact that I have to wait till the 9 month mark (vs 13, or is it 14?) means that I essentially get table scraps at popular resorts at high demand time. I have an occasional need to book Christmas/New Years week and that's difficult in some locations 9 months out. Just like it's also difficult at 10 months with Wyndham deeded. You will find out all this stuff. I'm by no means a Worldmark expert, but I do consider myself a Wyndham power user and know the limitations of what I own.