My big problem with critters is if they don't match what I think they should look like, I don't get them.  Take all the dragons DAZ has.  I have the mil dragon 2 and that's it.  Mostly because all the other ones look funky and I didn't want a low res sub-D dragon in poser.

As for what makes them look good...  I guess they have to pass the eyeball test, designs can't be out there, have an appropriate amount of details for the price, etc.

For mechs its all about the design. 

WARK!

Thus Spoketh Winterclaw: a blog about a Winterclaw who speaks from time to time.

 

(using Poser Pro 2014 SR3, on 64 bit Win 7, poser units are inches.)