I quite like the new asymetric castles - they look like real castles like the main castle in Neuremberg. The system X castles have the andvantage that they require a lot less assembling (I'm not a builder, so I don't mind having less versatility.)
I do have a lot of steck: at least two complete castles (3666 and 3667), three towers (Schuldturm, 3665 and 4063), a lot of wall/gate sets like the Castle Assault, several other buildings and a lot of spare parts. I really love these sets, but when I moved house 5 years ago I had to take them apart and box them, and I haven't got around to reassembling them - partly becasue I just don't have the time, and partly because I hate building. I also dislike the wobbliness of steck castles, it's not easy to pick them up in large sections and move them without the risk of everything coming apart.