I haven't noticed a slowdown. When I want to sell something, I price it aggressively and it sells quickly.
I was in the market for a 35L. Some people here linked me to one that I hadn't seen. The person was selling it for like $85 less than new. I mean, come on. I'm not saying it wasn't in like new condition, but it's just not worth taking the chances of buying used to save basically nothing.
Also, the pattern in the sell forum is people want their items to remain on the front page as long as possible, so they price a bit higher than they really will accept, and then progressively lower the price which is an allowable bump basically. Everyone knows this and just sits back and waits for the price drop.
I just bought a Sigma 12-24. He was asking $550. The lens sells at B&H for approx. $690 so the price wasn't bad. I offered less, we met in the middle, and I got a fantastic lens and saved close to $200. That's almost a third off. That made it worthwhile.