You can review list prices by going to Deere's Build Your Own site. That will get you into the ball park and help when deciding the relative merits of the different models.

This is the only model from Deere with power steering and hydraulic deck raise and a 42" deck. The tires are relatively small, so the ride won't be as good as going to an X500 series.  But to get power steering and a 48" deck in that series, you need to go with an X540 less deck and order the deck separately. It's a big jump in price. In between, there is the X360, which still gets you the power steering but with 48" deck. The tires are sized in between the X310 and X540, so I expect the ride would be in the middle as well.

I don't know where your Cubs were sized, but tire size and weight should help determine whether you are going up or down in ride quality.

If the power steering isn't important to you, then your choices go up a lot.