I am also testing at the moment. So far day 23, level 26, Engineer, SP.
I think mostly it's good. The thing that I'd change, given my current experience with the mod is making iron club and spiked club recipes cheaper. For 20 days or so I've been running around with a wooden club. Mostly because scrap iron is so hard to come by, I don't want to waste it on a club. Also I don't want to spend my hard earned skill points on clubs.
I finally made it to Iron Processing during day 22 and now have a full set of engineer tools. Yieehaaa! I have to say though, I am kind of disappointed by the iron ore yield. Not using a stone axe to grind down those 25k (or 2.5k?) hitpoints pip by pip on a single iron ore block...okay. Absolutely at your side here. But even with the proper tools the yield is so low, I don't know if I can build a proper fort with it. An entire iron ore block basically comes down to one forged iron. The amount of tunnels I'd have to dig to get an even decent amount of iron.... Okay, that's my first impression, maybe it'll change later on but at the moment I think the yield can easily be doubled without making the game easy. There's a difference between difficulty and grinding.
Otherwise I am working on those story texts. I am trying to give each profession three different background stories.