This is the model Grizzly I own.
http://www.grizzly.com/products/g0513x2/images/
It has been a great machine, tracks nicely, plenty of power and is pre wired for 220v.
The reason behind wanting cast iron wheel is that it gives it mass and that if I remember right means better cutting power.
I have seen their models in the store, as I live near a Grizzly and the cast iron tunnions are a big step up from their base model.
No problems resawing with a 1/2 or 3/4" resaw blade.
I'm not overly familiar with other makes but I have heard good things about the Laguna. Good luck in your search!