Q400 doesnt have oxygen mask so it could only go up to FL250. There is an option to get the mask but Bombardier will rape you fo them to Horizon didnt get them. With that option you could only go up to FL270, so its not really worth it. At FL250 we see normal TAS of about 365 to 372ish. I've seen ground speeds approach 500kts on a good day. Normal speeds sit right at around 390kts.
Turboprops get their optimal performance at about FL190 to FL210. Q400 is an awesome plane when it works..You get the speed, size, and better automation than any RJ out there. We are the only turboprop in the US that is certified for single engine CATIII, not that i would ever want to see that day but the RJ cant do that yet. (They are fun to do in the sim but dont want to come close to that in real life)
