Not trying to influence your decision but
http://www.rvwholesalers.com has the Equal-i-zer for $399.00 including shipping if the price is your primary concern. We got our 600/6000 from them but found their customer service was better than their bookkeeping. I ordered over the internet and when I didn't get an acknowlegment in a couple of days I called them. They said it was out of stock but they would send one from another location. It arrived, I installed it and all was well until UPS showed up with another hitch a couple of weeks later. I refused delivery on that one and got a call from them a few days later wondering what was wrong with the hitch. They seemed both puzzled and pleased at my response -- they had billed me for only one so I suppose I could have kept both but who needs two of the things. I suspect they have patched the hole that let that happen by now.