Trading in this game is interactive, engaging, consistent, and believable. It's also a lot of fun, and can be quite exciting.
Interactivity? Sure, you do get to navigate menus and peruse lists and even push a few buttons.
Engaging? That's a subjetive criterion, we can't evaluate it objectively, so I'll just go with NO because I know it will make you pout.
Consistent? Definitely not. There's ample evidence of that. Check
THIS out. I've described a similar experience myself, in this very thread.
Believable? I guess it depends on how much you want to believe. It does have some nice touches, like floating prices according to supply and demand, but on the other hand you have wealthy systems with five billion people living in them and no module above class 3. Why is that? Rich people don't like nice ships just because they happen to live in an agricultural economy?
And how come 5 million people working in a high-tech system can't offer more than a few thousand units a day of only one or two high-tech commodities? I mean, it's a space station, it's 3301, it's supposed to be full of assembly bots, and yet the output is a fraction of what could be accomplished by the inhabitants themselves, armed with toolboxes and some elbow grease.
Not only it goes against basic principles of economics and virtually all the best practices of marketing and sales, it's also full of artificial scarcity, with the explicit goal of extending your travelling time. I suppose some people would find that kind of time sink delightful, but I'd like to spend more time actually trading, rather than just running around.