I enjoy selling on etsy. I do 80s and 90s toys (link in my sig). I don't make tons of money at it but it's a fun hobby and allows me to pick up vintage toys when I find them and have a way to pass them on. I've had several customers send me private notes (even one by regular snail mail!) thanking me for reuniting them with childhood toys. I really like that part the most. I'm hugely sentimental and toys have very real meaning for me and many members here can no doubt relate!
There are good ponies listed- anything from commons to more rares and accessories/merchandise. I find I do better selling in lots rather than one pony at a time but that probably depends on the pony, what you had to pay for it originally, etc.
I like the ease of etsy with the payments and templates. I have to pay fees, of course, but I find it's worth it for the protection you get and audience the product is exposed to. I do NO advertising and average about 10 sales a month. Since I'm not making any kind of living at it, that works just fine for me! Plus, the fees are considerably less than ebay. I think etsy fees are like 3% of the final value (can't recall exactly off the top of my head) and when I sell on ebay, I figure more like 10% at a MINIMUM. That's a big chunk of a small profit, you know?!
If you decide to sell there, I recommend reading through some of etsy's suggestions on how to set up your policies. You can avoid some sticky situations with a thorough policy section.
Anyway, overall, I've been pleased with my etsy selling and buying experience!