I love my P90DL (April 2016 build) - great for going cross country (though I do envy the more recent MXs with greater range). Ludicrous mode is fun on occasion, but I prob activate it less than once annually, so don't pay a big premium for it!
Had a 2016 S and switched to a STD range X - got back into a loaner 2016 S the other day and I was truly delighted with my choice to change to the X. S IS quieter AND quicker with more range - but the X is a total fox to own and feels so roomy and airy. Its smoother
I'm definitely keeping my Model S P85 until it dies! Hoping to get to 400,000 miles. I test drove the Mx P100 a while back and liked it. People experiencing problems is a concern but with warranty, i'm hoping that will be okay.
You can keep it on Ludicrous all the time - but the acceleration is a little jarring for my wife (snapped your head back...), so I keep my X in "chill" mode most of the time unless I feel the need to show off a little...