The machines themselves are generally decent to operate. I have been around shred technology since ethe early seventies and they have only improved.
With regard to C&D however, I like to find out what it is that you are looking to do with your waste stream. If you are simply wanting to reduce your volume to the landfill they will fit that bill, but if you are looking at recycling any of the waste stream then I would suggest looking into a sorting system. There are lots of options in sort technology out there, but all of them recommend not shredding before sorting. You could put 250,000 into a really nice sort system and start making money off the recyclables. It just depends on where you want to save money, both will reduce landfill volumes but sorting can put money back in your pocket.

We are really just trying to find some machines that will cut our waste volume in half. There is a few machines you can buy now for around 90k a Proto grinder that has been rebuilt. So we'll see how it goes.

I have worked with Vecoplan in the past and have found them to be reliable units. they can certaily do the trick for reducing volumes. Good luck in your search, If I run across any good deals I'll post em on here.