A couple of folks have asked about studless building: how tough is it, how is it different, is it “better” or “worse” than the conventional (studded) way of building, etc. This is not an answer to that – this is just some ideas and thoughts on the subject, take them for what they’re worth.
There are certainly some difference. Prime among them, I find studless building to often be slightly “sloppier” than conventional LEGO building: often the end structure has more give and play in it than a similar studded structure. That’s a disadvantage when you what high-accuracy mechanisms, for instance. The flip side to this is studless structures often seem less likely to fall apart, due to being held together by pins and axles that are often stressed in shear instead of in tension. That’s a nice advantage, particularly for kids. Although it leads to some problems when you need to make small changes in the center of a mechanism; you sometimes have to disassemble a lot of stuff to “fix” what needs correcting.
Another factor is up, down, & right angles. LEGO studded structures traditionally have a specific top direction (“studs-up”, though they don’t have to) and to consist of almost exclusively right angles (although again, they don’t have to: hinges are often critical parts in getting some shapes for just this reason). With studless construction, these limitations are removed. In fact, quite often a robot ends up with many non-right angles and oddly-“bent” or sloped sections. For instance, for strength, you can often easily arrange to have a triangle construction in a studless build… but that means at least one “non-right-angle” piece, that may be difficult to join to later with the exacting LEGO geometry.
Finally, I’ve got to say that hybrid structures are certainly worth exploring. For some things, studded frameworks have great advantages (rigidity, for instance) while for other studless mechanisms have the upper hand (light-weight, reconfigurable structures). While I’ve recently become locked into a “no studs” mode of building, there’s absolutely no reason why both can’t be used to compliment each other!