One of the things I always loved about modo were and are the quite intuitive modeling tools. Now I don’t model that much with subdivision surfaces (don’t ask me why, but somehow it seems to me that they are always doing this for films even for background stuff just in case someone might show a close-up and then end up with massively over-detailed SubD meshes) and operate on pre-existing converted CAD data, but if I were more into the design side of things, MeshFusion would definitely be one of those must-haves. I had a chance to test it a bit while it was in Beta, and if I had had it back then, I could have modeled a hundred household chemicals bottles back then. It really makes my detergent bottle crafted with conventional vertex pushing and pulling look even more crooked than it already is. It’s a great timesaver to create complex shapes with just a few operations and the best part is that it remains editable and interactive, so you can experiment around and are not committed (up to a certain point, of course, you still need to work out some specifics of the resulting mesh by hand in many cases like when you need a specific edge loop for a sharp corner or similar). It’s actually quite fun to just doodle around. There’s a somewhat similar tool for Lightwave, BTW, if you don’t have modo (yet) ;-).