I've talked a lot about Panzerschiffe in the past, so I will concentrate on companies that cast in metal today. I now have experience with four of these. (Well, five, really, but I'll leave the last one out, as it's a rather special case and if I ever commission their ships it will be as wreck markers.)
To wit: I've bought and built cast metal models from GHQ, C in C, Superior, and Viking Forge. All four make quite acceptable ships, though I tend to invest more work into some than others in order to make them match my mid 1942 ideal target date.
I'll start with GHQ. Scuttlebutt from experienced mariners generally has it that they make the best ships, and their models are indeed lovely. Other builders give them a run for their money in one way or another, but they're quite worthy ships. Even so, I find I need to add a few fittings. (The occasional mast or radar set, for instance.) To model USS Bunker Hill I used a GHQ "CV-10 Yorktown." I bought her from a surplus auction rather than new from the builders, so fitting out required a little more work than usual as the 5"/38 twin mounts were missing. Still, when you can save your taxpayers 75% of the cost of a capital ship, you find a way to replace those missing DP mounts.
I went a little further, though, opening up the hanger by drilling holes at the bottom of the cast on roll up door, cutting out a series of triangular sections, and then clipping/breaking/jiggering off the remaining teeth and filing away the excess to square it up. The floor was made of a piece of sheet styrene. The deck was a little thick, leaving the overhead unpleasantly low at the hangar door, so I filed the visible portion of that down as carefully as I could. You can see the result.
You'll also notice that I added a spar and homing beacon to the top of the mainmast. (Not really sure why GHQ doesn't depict those, since they include so many other fiddly bits.)
With a nice coat of MS-21 Navy blue and some deck blue stain (Apple Barrel Navy Blue and Midnight Blue, in this case) you end up with a fairly nice model. In this case I actually did base in grey, giving a somewhat brighter look than some of my other MS-21 offerings. I used a very dilute black wash to add shadows, brushed on another light coat of my primary color, and highlighted up with a variety of lighter blues and greys to give it that weathered, sun-faded look.
Making Katsuragi out of a Superior Soryu comes in the next post.