I have been using Cubase since 1997. They called me the "Cubase girl" back in the days when I would come to Guitar Center in Boston. I also won a contest Steinberg USA held about 3 1/2 years ago and as the winner for the Grand prize, I was flown to the Hamburg headquarters to meet all the great software developers and folks there.
** Why Cubase **
Built-in instruments such as Groove Agent, Halion Sonic. Once I figured out how to work with the built-in instruments (the last 3-4 years or so) I realized that the sky is the limit.
Cubase is truly a production power-house. I also love the features and UI since I've been using it for so many years. Sound quality is top notch.
The only limitation for Cubase is 8 inserts per channel that can be frozen, versus other daws like Logic which don't have a limit to inserts. There are work arounds for this, but it's not optimal.