One difference appears to be the Husqvarna has a Tuff-Torq K46CR transmission where the X320 has a Tuff-Torq K58 transmission.
Here's how they compare per TuffTorq:
Tuff Torq Corporation
The K46 is a weaker transmission but on the plus side it has an automatic diff lock in it where I don't believe the K58 has that feature.
So with the Husqvarna you have a bigger engine but a weaker transmission. I suppose you could look at it as being able to cut tall grass a little faster but for pulling and pushing anything the Deere theoretically
would hold up longer before transmission failure. Theoretically being the operative term there as it does not take into account whether the transmission was made on a Monday or a Friday.