So you have a lot of good points.
Preston McCauley

I agree with your concerns. Initial launch times are too long. It’s fast when you get in, and I usually keep my tabs open, so not a huge deal. Also, are you using their desktop app? I find that it makes it feel way more… real or something. I dunno. More sketch-like.

I’m almost always online, so I haven’t experienced the offline pain yet. I’m hoping that it doesn’t present itself, but it’s a valid con, for sure.

Also, I think the Sketch import is less than perfect. It does the job for a lot of things, but my nested symbols and overrides just took a fat dump when I tried to import them. There must be something strange about how Sketch handles those, as Principle also still can’t cope with them. Not sure why. I’d like to see an option to specify what pages within a sketch file to import, as doing it all at once is a little too much. There’s room for improvement, to be sure.

I view the cloud discussion very much the same as when Google Drive first came on the seen. I think that in 2–3 years time I’ll cringe at seeing a local design file just like I do at seeing a local Word doc, but I realize that there is a place for both, maybe just not for me. Not sure if they have a local backup option. Would be worth looking into.

It’s gonna be fun to see how this all turns out, for sure.