I prefer the original FS1 for the slightly different menu interface and sounds in it. I think that's what most people mean by "feel."
Actually the game itself plays very differently, as in the functions regarding the turning, firing, hitting, etc.
Not sure what's related to it or what changed on the FS2 crossover, but pretty much everything worked in a slightly different way. At any rate that's what I feel when I play it.
I used FS1 as training whenever my FS2 skills dropped. Something about it is harder and requires more precision while it comes more easily in FS2.
At any rate, as I'm not a technical kind of guy, it's hard to explain or check the numbers, but I could say with 50% certainty, that I'm not insane (naturally, there's also a whole half chance that I am insane).