I can agree with everything above.
I am a Casual RPer and don't get myself mixed up in group RPs. Honestly, it's too much to work with.

A con for Free RP: lack of development. Out of laziness and boredom, I did a 1x1 RP with a Free RPer and quickly abandoned it for lack of vocab. I usually don't care about vocab if you have a long post & vice versa, but simply just saying, "he said" or "he smiled"? Srsly?

And speedposting is an amazing experience if you are in a 1x1 RP, with the only partner that's replying.

My own stigma on advance is my lack of proper sentence structure and simple spelling mistakes that I mostly don't bother going back to change unless I happen to be re-reading something. I go in write it and don't look back. I sometimes add in commas and the like but not always. Sometimes I make really stupid mistakes and I'm just too lazy to go back into. I was once free-level but I grew into casual and the high casual as I wanted to develop better stories and actually give my characters some depth without the need for seemingly like I'm putting in to much work for free. I simply don't have the quality to consistently make two paragraph posts or those massive eight paragraph posts I tend to see in advance that make me shake my head in wonder in how much time must have been spent on those posts that consistently are that big.