I ended up going with the Toro 5000 Series. It was the most expensive of the bunch by a couple of hundred $ but it had a lot going for it too. Larger engine and hydros, longer warranty, and the dealer threw in an extra set of blades, 12 gallons of gas, some oil, free delivery, and cut me a huge break on an Echo trimmer. I spent about 3 hours yesterday playing around and cut about 5-6 acres of very heavy (12"-15" in spots), juicy (we just got 4.5" of rain two days ago) grass and weeds. A mixture of St. Augustine, Bahia, clover, dollar weed, and misc other stuff. The mower chewed through it like a starving dog. It only started to bog down when hitting the thickest stuff at almost full speed. In the rutted up pasture, the isolated suspension seat was worth it's weight in gold! I did manage to catch the edge of a muddy ditch and got stuck once. The old New Holland tractor is still good for something as I had to use it to pull the mower out. It looked like I had gone mud bogging with it at the end of the day. All in all I am very happy with the purchase. Thanks to everyone for their thoughts and insight!