Hello all, new member, but long-time player of Avernum (1,2,3, BOA, and now 4)
Even with prior experience, I would say this is at least as difficult as prior games in the series, and I'm not all the way through (about level 20 or so).
I found myself more frequently reloading if I bumbled into a big fight without really preparing and planning, which meant more strategy was required. Even the smaller battles required strategy because I wanted to be able to get through using the least amount of mana, since resting was not an option.
I found the first aid aspect an interesting and welcome change. The death/unconscious feature means death is not an instant reload, which I liked too.
Overall, I'm liking A4 quite well. I think there's a tendency to not like things we aren't used to at first, but now I think many aspects of the engine are indeed superior to the old ones.