I bought this game after playing and enjoying Capitalism Plus. Pat3 is another fun economic game. While playing, I was reminded of the Tradewind Series. The trading aspect is almost the same and enjoyable. But I find the combat in Tradewinds better. The Capitalism, Patrician, and Tradewind series are my favorite economic sim games. Hope to see more good econ dos games. I prefer dos games as I know that Dosbox is a pretty reliable emulator. Older windows games are not always reliable to run on my computer. If I enjoy a previous dos game in the series, then I usually give the windows sequels here a shot.

Well, I do have played Tradewinds, Tradewinds 2 and Tradewinds Legends (the latter two I've even completed), and while they're certainly fun games for someone who hasn't yet played trading games before, and somewhat enjoyable for those who have, I've found they're nowhere near the Patrician games in complexity. For instance, buying and selling goods (thus, changing supply) in any given town has no effect on the price of the goods - you could buy hundreds of crates of anything and still pay the same, which you can't do in the Patrician games. Also, while the combat is rather boring in the Patricians, I think in the Tradewinds games it's outright yawn-inducing.
If you're interested, here is a short "blurb" I wrote for then Tradewinds games (on occasion of Tradewinds being the free game of the week on Sandlot games).

I'm amazed someone thought of the Tradewind series too! This was the first thing that came to mind, having played Tradewinds legends and 2 first, before Patrician 3.

And the prices of good in Tradewinds does change. Hitting save and reload is your best friend. However, in general Tradewinds have a more seasonal approach to supply and demand. Like in January, goods will be priced low in a certain city, and in the next, priced high. I think playing the customized game, where you create your own character, does randomizes things more.

Indeed. What I meant was that there's no supply/demand effect on the price of goods. By using save/load and/or listening to rumors, you can get a ridiculous amount of money, insanely fast (which, however, you can't invest in businesses like in Patrician 3).

Yes, most certainly. Patrician 3 is definitely the winner here, in terms of economical complexity. And you can randomize even more the ports and rate of production, using the map creator as well.