NetOne Desktop version has better copy/paste and you can't use external image editor for sprite editing with Browser. Those things make the iteration process slower. That's why I still prefer C2 even though I've C3 subscription.
the only copy paste difference ive noticed is that it confirms that you want to copy, as when you click copy on that object, you're really copying a script, and your computer is making sure that you know this, as some things will hide scripts so when you paste them they run malware.
this is not a issue with c3, but with the internet in general.
that aside, i believe you can turn that off.
also, once you've run it from the browser once, you can run it offline, which was my major concern as my internet disconnects a lot, but offline working is very nice.
honestly, i've seen a lot of people shit on construct, and say "i dont use it because x and y" , but x and y usually arent even real issues, just something they heard a friend say or read on a forum.
as for editing sprites, edit them on your desktop in the editor of your choice, then import.
i dont have a subscription, simply a registered account, and im more than happy with c3s capabilities, even with the hashed event limit. i recommend it to anyone i know interested in programming or games, and have made upwards of 30 seperate games and apps , though few of them are published. however, great software. keep it coming.