I purchased a Citation about 2 weeks ago. As for ride, in my opinion there is a huge difference, I tried several Hustlers, Country Clippers, Cubs, XMark's and Great Danes, as well as the Ferris 1500. In my opinion the Citation ride was superior, Ferris next. Simplicity bought Ferris in 2004, so the Citation and 1500 are closely related. The IFS system has been used by Ferris since 1998 and has proven itself effective.
My yard isn't golf course smooth and has a few slopes, I wanted to make sure all wheels stayed on the ground, they do with the Citation, I've only mowed my yard three times but have been pleased, I cut my mowing time in 1/2, the other day I mowed it in 45 minutes, used to take 2 hours, around all the trees etc..., that was a trim mow and I mowed at full speed with no problem, my brother-in-law can barely mow half speed otherwise he needs to have his kidneys relocated to their original location.
I haven't adjusted the shocks either by turning the shock or moving it's mounting position, I have read one person's post who bought the Ferris 3000 and he did make some adjustments. I do think if you had a traction issue the 90 degree mount would help there.
As for discharge and quality of cut, I used to bag some of my yard, the Citation spreads the clippings nicely so I don't think that is going to be an issue, quality of cut is very nice, especially at the speed I'm mowing, I won't mow that fast all the time but I'm experimenting. It also has the stripping option but I've not tried that yet.
As for mowing tall wet grass, I simply haven't done that and was told never to mow with a ZTR on wet grass, especially if you have slopes. My first mow the grass was taller than usual and again, I mowed at a high speed and cut right through it and looked fine.
Tip speed, I asked about this when I was initially looking at several different mowers but I can't remember the number, I do recall they were all very close.
This unit is marketed as a commercial unit and from everything I've read or was told and from what I've seen compared to other brands, it's commercial, the pumps are commerical grade and the same pumps are used by other manufactorers, i.e. Scags, Dixon etc...In researching the pumps I only heard good things about these pumps, that's not to say their the best, I don't know that, all I can say for sure is that they are commonly used and are considered commercial.
As for the Briggs & Stratton Big Block Van Guard, I personally don't have concerns. Briggs has been building engines forever, I have had good success with Briggs engines and my first riding mower which is now 18 years old, had a Briggs 18HP V-Twin and I changed the oil at the start of each season, as well as the plugs, changed the air filter once, but cleaned it each year, gas filter once and it's still running and I used it like a tractor. I just gave it to my father-in-law and he's mowing 5 acres with it, so with that history, no I don't worry about the engine. I also like the fact that the Briggs has a oil cooler, that can't hurt.
All in all I'm pleased and I purchased my unit for $5,565 with 6% sales tax included. The Ferris 1500 which is the Citation cousin would have cost me over $6,100 and I liked the fact the Citation had headlights and also rear roller on the deck. I've also done business with the guy I bought it from for years.
I hope this helps some, I know it's a hard decision, I was driving my wife crazy trying to decide, she did a search for ZTR safety on the web and found articles about mowing slopes with them and that keeping all four on the ground was a must, so that sealed it for her and thus for me. Every unit I looked at had something I liked over others, in the end I bought the one that meet all my needs. I wish you luck!