I built Robie house, and frankly it's nowhere near as good as Fallingwater. Way too many of the pieces are 1x1 smooth tiles that are placed all over to look like paving stones, and most of the walls are just 1x2 red bricks stacked over and over. I like the look of the finished model, but as a build, It's not great.
Also, inside, it doesn't have the multiple floors that Fallingwater does even though Robie house is a multiple floor building. Frankly, the set is sort of a disappointment.
Also, am I the only one who mainly build Technic stuff? Since I got back into Lego a few years ago, those sets have been the ones I've really enjoyed. Maybe it's because I'm an engineer and not really all that into Star Wars or other licensed stuff. Some of the bigger Technic sets are really cool, IMO.
I just actually finished the Uni-mog, which has some col use of hydraulics. The actual power stuff isn't that exciting (just a winch and spinning the crane), but the suspension on the thing is cool, I love all the gearing, and the hydraulic controls are cool.