When I started Project: Eisenritter, I couldn't help but think the design was a bit lackluster. Later on that seems to improve some, but by Floor 12 I was disturbed by one of my worst pet peeves of Wolfenstein 3D games - full out boss guys being used as normal guards in some cases. It reminded me of many Mario/Mega Luigi mods, and I ended up quitting for that reason.
So I was a bit skeptical heading into Operation: Heimzahlung, but now I've made it to Floor 16, and to my surprise, it's been a great addon IMO. Hard guards are used to guard many key items, but they are not just flat out bosses. And the design seemed, at least, to be on a par with Eisenritter, but I've enjoyed it a lot more and plan on finishing it for sure.
But those are just my opinions, and most people seem to praise all his works. So that's why I'd like to see the overall answer to the question in this poll, in addition to any comments you may have to make.