It's kinda hard to tell what with ease of build & price being the apparent priority for many, but my gut feeling regarding "look" goes something like this (not my opinion for or against - jus' what I've observed lol);
#4: Mountain bikes
Like I said tho - it's jus' a gut feeling as there's a bunch of factors in play that may be more "important" than look when folks build a bike themselves, not just price or even ease of build - but what type of riding style, region, engine type, tool and resource access & experience, etc, etc, etc. Building a stylie ride tends to be later, after they've built at least one and dug it so the stats may be skewed.
As an example, I really like the trikes & bikes with sidecars... but they way the roads are around here they'd be problematic as we've no shoulders to speak of lol, whereas in Arizona that may not be such a problem - but I'd
want a rippin' off-roader were I there *shrug*
Best bet? A selection - ppl like all sortsa different stuff, including options in pricing