Seems like GamersGate is having a buttload of them on sale this now. I'm a huge fan of Koei's Uncharted Waters, mostly on Uncharted Waters 2 which is one of my favourite games of all time and I've played through it 12 times, 2 times for all the 6 characters. Have not seen any high seas trading game that can match up to UW2. Sadly, the UW franchise has now become an MMO.
So I'm looking at these games on offer now:
- Age of Pirates: Caribbean Tales
- Age of Pirates 2: City of Abandoned Ships
- Tortuga - Two Treasures
- Tortuga - Pirates of the New World
Are they worth getting? I'm leaning towards Age of Pirates.

From that list I've played only Age of pirates1 (so patched up it was like a mummy) and considering it's a buffed version of Pirates of the Caribbean (aka Sea Dogs 2), I didn't think it was too bad. Of course, the storyline is really pathetic, but I played it for the sea battles anyway. To tell you the truth, I'm down right pissed that they can't make a good 15th-18th century ship simulator game with an impressive storyline. The best that Akella made was IMO Sea Dogs, and from then on they (and others) made so little advancement that it's just pathetic. I know there's little market for it, but at least make something half decent and let people mod the shit out of it. Pirates of the Caribbean got a boat load of mods, and it was a better game with them, but alas the community built on bad and unfinished foundation and could only do so much. There, that's my rant on this issue.

Bah, the only good high seas trading / pirate games are High Seas Trader & Pirates!
Patrician 3 was also pretty damned good

Having also been a fan of the Old Koei games Uncharted waters and New Horizons, I have yet to find any game that has in my mind lived up to either of those two.....
Patrician 3, was ok, but you kind of have to change your expectations overall gameplay.
/sigh I wish Koei would go back to the old ways, Romance of the three kingdoms anyone? Cletic Tales Balor of the Evil Eye? /sigh now im all nostalgic.....

Just so you know, a casual high seas trading/pirate game "Tradewinds Classic" is being offered for free this week only.
www.sandlotgames.com

I've played both High Seas Trade and Pirates, they aren't as good as Uncharted Waters 2. :D
Romance of Three Kingdoms, hehe, another one of my favourites, also one of my favourite history interests. I played RTK 2,3,4,5,6 and then skipped to 11. Genghis Khan 2 is another awesomesauce game. KOEI mentioned they will probably not make another RTK game. Sad.
Too bad Koei is busy spamming Dynasty Warriors and MMOs now.