TRACKER
None of them should have a plastic trigger guard - it is an intregal part of the action of that gun.
There are several small differences between the Z5 Omega and a regular Omega and I guess they all add up...
Here is my take on the whole thing - if this is going to be a gun that is used on occasions for short hunting seasons or to extend your season the Z% will be great. If this is going to be a lifetime gun and a gun you are going to shoot a lot - hunting and target parctice - then go with the real Omega abd even then I would suggest the true stainless model - not the weather shield that looks like stainless... which now brings up another problem... if the price of the good Omega runs up in to the area of the price of a TC Triumph - go Triumph all the way...
Look online for Buds Gun Shop and compare prices there.... not that they are always the lowest but they are close....
http://www.budsgunshop.com/