The Adira - could have been so good, turned out so bad! Refused to buy one and instead converted one out of an Octurion with a double central hull.
The Brivoki - although we've not seen the finished figure, just the prototype. Oh, hang on, we're not going to see the finished figure now, are we....
The whitestar carrier - but then again had an old whitestar in resin that was the right scale to use as a carrier, so used that instead.
Have to disagree about some others mentioned:
The Liati - with a good paint job it no longer looks like a flying dildo. And the pipes on the top, they are intended to have turrets fitted, the ship has turret mounted weapons after all.
The Dilgar fleet - totally disagree, they are one of the nicer and more original fleets out there, with a very distinctive style and a degree of elegence rarely found in a fleet.
Drakh cockroach (sorry cruiser) - Organic shape and smooth texture makes painting it in interesting patterns something of a pleasure, can certainly be made to look good.