"I am wondering how realistic the flight dynamics are?"

In my opinioni: Not very.

FYI, I too tend to be, shall we say, militantly frugal; after using FMS for six months and then trying a commercial sim package's demo version, I found the latter noticably more 'realistic' in its dynamics; so much so that I immediately decided I would have to find a way to afford the commercial version. I am happy with what I got for what I spent; I was not happy with FMS despite spending nothing on it.

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