I demoed a Steiner 420 (predesessor of the 430) a few years back and was impressed with everything about the machine. At that time, there were two local dealers, both about 30-40 miles away.
I stopped in at the first dealer and was told that there was only one person who knew anything about them, and that you had to make an appointment just to talk with him about the possiblity of a demo.
Not being overjoyed with this first experience, I called the other dealer. He was the one who suggested, actually insisted, I demo one. I was thinking just a 60" mower would be great, but he said he would bring along a slip scoop too, just in case. He brought the machine out on a Friday, and told me he'd be back on Monday to collect it. I felt really bad that after working numbers a few different ways with the CFO, we decided we just couldn't do it (a decision I keep kicking myself for).
Since then, one (the one I dealt with for the demo) switched to Ventrac. When I asked why, he said that when the Steiner family sold the business to Textron, many policies and practices that pertained to dealing with customers were changed for the worse - he didn't go into detail. Apparently, the Steiner family didn't like these changes either, hence their starting the Ventrac line as competition.
My choice, without a doubt, would be the Ventrac. Not because I feel it a better machine, but because I feel the dealer is better.