Search these forums, because this question comes up about once a week, and you’ll get a lot of opinions in favor of any solution you’d like to use.
What it boils down to is this:
1) Do YOU want to use a PC or a Mac? Whatever you answered, buy that.
2) What editing program do YOU like? You say you’re using Discreet now. Do you like it? Are you fast on it? Then buy it.
Every editing program and computer OS has advantages and disadvantages. There’s no way to determine exactly what you need for a particular workflow, because everyone has personal preferences based on their situation.
You’re going to be stuck with whatever decision you make, so make it yourself.
good luck,
Carl