mtmower, some of the things you mention are classic Exmark traits.
The deck - the ultra cut deck does do a great job at lower speed but I agree with TLS, it is not a high speed deck. It's just not designed for speed. That deck makes Exmark an excellent choice for walk behinds in my opinion, the lower speed, but I don't know if I'll ever buy another Lazer. Though, I must admit, I am intrigued by RED technology. It's the reason I follow this thread. I'm curious as to what the gph will be for these machines.
On the wheel spin - both the Exmarks and Toros seem to be more susceptible to wheel spin. They both have very rapid acceleration in the hydros which lends itself to potential spin out. If you are a solo operator, you eventually get used to this and you account for it. But with employees, it can be an issue because they are not going to be as careful as you.
Jerky controls - if you are used to Scag, Hustler, or JD, the controls on the Exmark will feel jerky at first but just like the hydros... you'll get used to them. I actually laughed when you mentioned having a hard time holding a straight line when you started mowing with the Lazer because that's exactly how it is.
Every machine has it's pros and cons, I guess, and there's no doubt that Exmark does make some fine equipment.