I am confused by a couple statements in this thread, as I have a X534 and I don't believe it is much different than the other 500 series models other than I have 4WS.
I can not attach/detatch my 47 snow blower from the comfort of the seat. I don't think the way my blower connects is different then the others. I have to manually remove the belt front the drive pulley and manually pull the pins to disconnect the blower from the mount.
To remove the mower deck requires reaching under the machine to release the drive belt tension and remove the belt, then pull the pins for the rear connections and up front pull the pins also. Then you have to drag the deck out from under the tractor. I don't know about other models but I have to trunk the wheels full to the right and drag the mower out the left side with the gauge wheels rotated 90 degree so the deck can roll sideways on them.
I like the power steering and power lift for the mower deck and blower. I wish the snow blower lifted a little higher but I can get by with the way it is. I have the linkage adjusted for max lift in case you are wondering. The x534 has plenty of power for the 47" blower.
One other thing mentioned by others is that they could not get a 48" mower deck with some models. I had no trouble getting the 48" deck with mine, it was not special ordered either. I don't know why this deck width would not be available with any 500 series machine.
The power flow bagged is the best, don't leave the dealer without it. It's pricey but worth it if you have leaves to deal with.
I have 107 hours on mine after 3 years now and no problems at all. I've done all maintenance myself and not had anything other than scheduled oil changes, filter replacements, etc.
I would have bought a 700 series machine but the weight stopped me. The x534 with my butt sitting on it is close to 900 pounds, fill both grass bags and I'm sure its close to 1000#. That has me worried about ruts developing in the lawn so I use 5 different cutting patterns so I'm not running over the same paths from one cutting to the next.
I can understand the concern about moving the mower to the shed during seasonal changes. I have the same issue as I don't have enough room on my garage up Gunther house to stow the mower deck when the blower is mounted. I take the mower deck off back by the shed on the back of the lot and keep the blower in the garage on a low, flat cart when it's not mounted. The cart lets me roll it back outmoded the way during the spring and summer. Come winter I roll it out and mount it at which point I have enough room to park the tractor with blower in the garage where I can just open the door and go to work on the driveway. If I didn't have a couple hunfred board feet of oak and walnut stored in the garage I could keep the mower in there too, but that's not the case so I keep the mower deck in the shed over the winter. In mowing season which is about 9 months here I keep the tractor with mower mounted in the shed and the blower lives in the garage tucked away in the corner.
Please excuse the typos as I am typing this on my tablet and its not as easy as a full size keyboard.