I've now built several Mark II tanks and have moved on to a couple of Mark III tanks as well. While I sincerely applaud Alien Dungeon for going with plastic from the outset, there are several problems with the molds. One issue common to all of the steam tanks is misalignment at the rear of the vehicle. As you can see in the photo below, the smokebox doesn't line up well, nor does the inner track unit plate on the right side. These issues are easy enough to fix with a little judicious sanding.
In general I've also found that the alignment aids on all of the kits have been too large (whether they be pins or tabs), and all have required some amount of sanding before the pieces could mate properly. While the end result still looks excellent, it does require extra time that could have been avoided if the tolerances were set more accurately.
While somewhat annoying to have to fix, the miniature actually does build up quite nicely. Below is the first Mark III I finished assembling. In the top and front views you can see the putty on the sponsons:
Because the guns are plastic, cleaning them up and hollowing out the tips is very easy providing a very nice looking final product. I'm planning on getting all 15 of my American Steam Tanks together before having a marathon painting session (hopefully when I'm on vacation next week).