I've mowed four times with my X590, enough to be able to definitely say that on my property (lots of hills, obstacles, few open areas, about 2 acres to mow, give or take, hard to tell), it takes me a little more than half the time to mow with the X590 as it does with the 1025R. What used to take 1.5 hours now takes less than 1 (about 50 minutes). It's pretty incredible. The difference is how quickly I can toss the little X590 around. It's also significantly faster than my old X758 (about 1.25 hours).
And that's including all the extra spots I mow (between trees, side slopes, etc.) that I didn't even mow with the 1025R because it either didn't fit or would have rolled.
I thought it would be better to mow with, which is why I got it, but I didn't expect this.
mods...please change title/subject to "almost twice as fast."