Hey - if one fleet caught your eye, go with it.
If you like the look and character of a fleet, you'll generally play better as a result
The shadow box isn't as bad as it sounds, simply because there's no problem with using the shadow ships as war-level hunters if you prefer (many people avoid the hunter model as the coat-rack-o-doom looks....well.....a bit poo); as long as your opponent knows what ship model x represents and you're consistent about it, it doesn't really matter.
Painting wise, a black undercoat is perfectly presentable but doing shadow skin properly (fiddly as it is) really does make them look a ton better than just straight black. It's not quite so daunting as it sounds, as there is a little texturing on the hulls already.
Glossy varnish on top is also the way forwards.
They're great fun to play, and whilst they can be fragile compared to ships of a similar points level, don't mistake this for being easy to beat - and for that matter they can be annoyingly hard to kill anyway with a bit of luck - I've seen a pair of Var'Nic long range destroyers thunder in at it, firing everything they had. It took the shots, laughed off most of the fire and regenerated much of the remaining damage - before blowing the destroyers away in one slicer beam shot each. Total remaining damage on the shadow ship at this point? Less than 1/3 of the total.
Don't just try rushing at an enemy capitalship line; you will get shot to bits. But once you learn to use their supermanouvrability - they're like vree, but faster and better armed! - people will really get scared. Your insanely good fleet initiative PLUS a decent scout means that controlling the pace of battle isn't that hard.
Shadows are basically the ultimate hit-and-fade fleet, doubly so in campaigns where they don't have to pay to refit damage and have no crew expenses (other than brand new warships your only regular expense is replacement shadow spitfire wings); they can pick an enemy fleet apart over several games at no cost to themselves despite nominally 'losing' the games - then go on the offensive when there's no longer anything left capable of stopping a shadow ship in a one-on-one duel.
Oh - and the option of the shadow Planet Killer (the cloud). Has to be used once in a while. Just for sheer awesomness.
"What are you firing at?"
"Umm....that Escort Destroyer. And that one. And.....that one. Oh - and that one. And those two carriers at the back."
Slap!
Slap!
Slap!
Slap!
Slap!
Ka-blam!
"....I see. Would you like a nice game of chess?"
(I don't count the hunter - its not a proper Shadow). Try and play on tables with terrain and hit and run............. 
