very nice modeling Nigel,
I remember lego as only simple bricks (2,4,6,8 in the row or 2x2 or 2x4 or 2x6), but lego of these days looks very "restricted" in creativity. If you buy model of motorcycle, you can build just motorcycle, nothing more...
I was played with Merkur in my childhood and it was very flexible/open for creativity...These days are gone
btw, if you compare modeling between applications, is some of them "faster" in workflow (for instance if you want to build some kind of bike in both applications, is some "faster/smarter")