I replaced my Five Ten Freerider with the Spitfire. I made the switch because the spitfire has a softer tongue, which is definitely more comfortable on longer rides.
The only downside is that they are not as grippy with the Stealth C1 as the S1's were. It's great for trails and jumping for when I have to quickly move my feet. It was just nice to have the S1's grip like glue for DH.
I used to slip off my pedals dirt jumping, but not anymore. Only complaint is that I like to wear low socks and the tongue is so stiff that it digs into my skin. Issue can be resolved with socks that go above my ankle, but eh. Put a band-aid over the tongue for now.
They are a hassle to slide over the knee cap. If it weren't for the painful inner stitching that cuts into your skin, I would have tried a size up. While wearing them, the top mesh fit perfectly, but the bottom mesh felt way too tight causing them to be uncomfortable. Back in the box they go :(