Anyone have any opinions or experience on the matter?
My opinion, FWIW, is that you could just as easily write something like "Berserker robot" on a small square of paper and move
that across the board(/table/floor), according to some agreed rules, as necessarily buy/build a small plastic/lead model and probably also have to paint it. As long as everyone playing agrees that you're entitled to use such a berserker robot (fits the game, and keeps you within your army-points quota/whatever). Just like you can play draughts(/checkers) or even chess using just coins on a grid quickly scribbled onto a piece of paper or card...
The models are good for the visuals.
Official models are good for rewarding the manufacturer/license-holder. If you can 3D-print a decent figure (and, looking at current 3D-printer outputs, you probably can... possibly even without the need to retouch with paint if you can feed multiple colours of stock) then you're better for the first than the piece-of-paper method, and then you only have to worry about 'stealing' from the official manufacturer. Which, if you scratch-build anything (scenery, vehicles, even figures in the
style of the official figures, but using just spare bits, modelling clay and 'scrap'), you're already doing anyway.
I say do it, so long as you support the producers (to a degree that is inverse to the dominance of the market they
already have, perhaps... i.e. give more support the little guys than the established behemoths) by buying the official manuals rather than using pirated versions of those too, why
not try out a bit of 3D-printing? For personal use, certainly, even if it wouldn't be allowed in public tournaments and you'd need to re-equip yourself with official models once you decided you liked the game enough to try something so 'serious'.