I personally love the 400. It does have its quirks. Like I love when it leaks in the rain while sitting on the ramp. It does brake ALOT! That is a big issue with them, but the newer ones are doing better. The APU sucks when you need it in the cold it never seems to work.
They are a very fast and powerful turbo-prop. Normal 360 TAS cruise at 250. Ive seen groundspeeds in excess of 500 in cruise. The thing handels like a heavy jet rather than a smaler dash. I was once told by a very old time pilot that the feel system makes it feel just like the 777 he flew. Not sure since I havent flown a 777.
Avionics are nice not to many problems there that I have seen yet.
Oh the cooling and heating system is horrible. If your comfortable up front the people in the back are "normally" sitting around 82 degrees and complaining. Normal operation is flight crew is frozen and pax are comfortable. I think I have finally mastered the system and can "MacGyver" it in a way that it works.
Boots on a plane that moves that fast get tore up a lot. They should have hot wings but dont. There is a certificate for that but there is a problem with who owns the rights on it.
Theres more. Im just not thinks straight right now.