VSCO has a rather large following among the prosumer crowd, most of the Apple "Shot on the iPhone 6" ads mention VSCO and a photographer friend of mine uses it on his iPad with his 5D on the go. While I haven't used it myself, its certainly been name checked quite a bit and its success is largely due to it being a more empowered Instagram on the photography side.
I know pro photographers who use VSCO to edit their iPhone shots to upload to Instagram, as the tools are so much more powerful than IG's own. It's a great app.
