To add data points from two recent sales...
One was a frameset at $1,600. I listed it in every known Facebook vintage bike group and marketplace - no takers. Sold in a few weeks on ebay. The seller paid $1,848.75, including shipping, and I received $1,400.37. The fees can be hard to swallow, but reinforces that ebay reaches a much larger pool of buyers.
Second was a set of old but not vintage pedals. Listed here at $65. Sold on ebay for $90. Seller paid $102.60 and I received $82.55.
To be honest, it's much easier to list on ebay since you don't need to "bump" items and then either annoy forum visitors, or stop bumping and let the listing slide into oblivion. That said, I make an effort to list things here at a substantial discount because this is a great resource and generous community, and I really don't like sending ebay money.