I finally died. This may be a good time to share my impressions so far.
Overall it's rather easy to survive. No mobs spawning anywhere, it's almost like peaceful mode. The taint swarms are avoidable and easy to deal with. The starting apples last such a long time that it's trivial to set up an underground farm and never starve.
I like the implementation of various mods and their documentation. Even as a complete newcomer to Thaumcraft and Clockwork Phase, I could figure out most of the stuff without external help. This is the first modpack I've seen where you can explore the mods without having to read a bunch of guides or watch someone else play and repeat what they do. The starting book is great, just enough hints to keep the discovery process interesting, without the issues of HQM.
As a first playthrough without knowing the tricks and efficient progression paths, the progress was slow, painfully slow. Now that I know what to do, I still can't help but wonder how many will have the patience for this. If someone can only play a few hours per week, this is probably not the best pack to try... I don't know if there's going to be any rebalancing, but it would be nice to reduce the grind a bit.
The weather is the worst part of this modpack imo. Really, what is the point of that. At first it was cool to see unsuspecting witches being picked up by a tornado, but that wore off eventually. You completely avoid it by making an underground base, all it does is prevent you from building a house, unnecessarily limiting our options. You give us Chisel and Carpenter's blocks, and Ancient Trees, and then force us to live in underground dirtholes. I spent most of my surface time boringly climbing a ladder up and down. The weather deflector is gated so much into the end game, that by the time you build one you are probably not going to do much on the surface anyway. Maybe it could be improved a bit.