I deliberated over this for a long time as well.
I flew Arma2 with sometimes my Saitek X52 (sadly no pedals, but twist works for yaw) and more often with a Logitech gamepad (easier setup), I found this games flight to be very similar, but I can tell its not just the same old thing because it feels much more realistic. Like I am certain I am feeling wind currents and other anomalies become perceptible when pushing the aircraft too hard or too fast and I dont remember those feelings being in Arma games. I love it when a game kind of pushes me back to make me realize "hey buddy, this isnt some arcade thing, keep doing that and youre history". I'm altogethor pleased with this purchase so far and really looking forward to the career mode.
BI has done a good job. I feel like I can throw away the idea of MS Flight Sims soon, as they seem to be taking over the genre quite effectively. Arma was great and all, but I hope they keep making all sorts of sims, they clearly have a better understanding of what makes a good simulation experience than many developers of so called simulations. Eagerly awaiting Carrier Command :)