I have no personal experience with them, but the engines that have blown that i have heard about were stupidly expensive to replace. Just the fuel injection side was about 8k? You can buy a running motor for 1-2k
The scariest part i see is replacement parts, being a common rail fuel system, you'll have a high pressure pump, electronic enjectors, turbo, then an ECU to run it all. I don't know if it's a stand alone system that is contained on the motor, or if the skid steer does these controls.
Older machines can have issues, but depending on what you want from it, it may be ideal.
Pesonally i avoid hand/pilot controls. Steering levers for back and forth, feet for lift/tilt, thumb switches for aux hydraulics.
What are you planning on lifting? 90-100HP is a really big machine, my S250 i think is rated for 2500lbs, it's 70-80hp, my S150 is about 46hp and is rated for 1500lbs i think,