I have a 2016 x590 that I bought new in the spring of 16. 54 inch deck, MCS, power sleeve hitch, power shovel.
Overall it fits my needs. I have 6 acers, 1.5 hilly to mow and the rest forest. I would buy it again.
Things I like: EFI and power steering, I wouldn't give either one up.
Power shovel-works good for loose dirt, mulch and even processed gravel. Pretty easy to install and remove. Occasionally blows a fuse lifting something too heavy, I keep a zip-lock bag full. I have moved a tri-axel dump truck of processed gravel with it to smooth out my trail in the woods and maybe 15 yards of top soil other the 3 years. I would buy it again, it's definitely not a loader, but it serves my needs.
MCS- would not buy again. I would buy a cyclone rake instead. MCS hard to mount/dismount, can't pull a cart with it installed, can't have my power sleeve hitch installed with it on. You have to adjust/level the deck when you mount/dis-mount it. Doesn't fit like a factory option, the discharge chute is butchered to install. If I only mowed, then it would be ok. I only use it in the spring and fall because the Gator blades do a good job throughout the summer..
Power hitch-Yes would buy again. I have only used a landscape rake with it but it's worth it to me. There was a problem when first installed by the dealer, it would cause friction on the mower lift arms and they wouldn't fully lower after the deck touched down and I had to pry them down to disconnect the deck. I took the seat/fenders, running boards off and lubricated the flat bar steel pieces and it works like a champ.
Locking diff-small detail but I use it a lot coming out of the woods with a cart of firewood, I have a steep hill to climb.
I could see stepping up to the 700 series for the quick connect deck but I don't need a 3 point and it still doesn't have a loader option. If I did a lot of ground engaging work then the 700 series would be a better choice.
Just my thoughts.
Oh, and the wife pulls a cart around with it so EFI and PS aren't really a choice. lol