I personally like the mid production builds. They always seem more customized than just plain early or late. Please excuse me as I'm not trying to sell you something, just help a bit....
Our metal hull comes with upgraded suspension arms. Ours are the type held in by a set screw on the suspension arm so you dont have to worry about stripping the plastic/metal arms. It also comes with a metal torsion bar system that is pretty easy to tweak individual arms to your liking. It also comes with a metal plate to mount your gearboxes to help with flex in the chassis. You also get the rear torsion bar/track tensioner as well as the easy open latch and catch. It is quite the upgrade although I'm not sure if the Mato road wheels can be reused. Our idler wheels are now two piece screw together type (new ones ship when the T34 comes in stock) for the Tiger 1 and since they are held in by set screws they should be a lot more reliable as well.
Once again I apologize if I sound like a salesman, I really hate that.