Is it worth going to so much trouble with Ethernet differential tracks?
Consider this:  According to the Ethernet spec, a standard Ethernet connection is allowed to go through up to 100 meters of cable, including several patch cables, patch panels, etc.  

Then look at your PCB and try to imagine how your trace matching will influence the signal integrity given the overall Ethernet connection scheme (cables, patch bays, etc.).  It is unlikely that anything you do in 1-2 inches of trace length will be as bad as a typical patch panel or wall jack.  

But...  The better you route your signals on your PCB, the easier it will be for you to meet EMI regulations.  It is impossible for me to say how much easier it will be, but it will be easier.

My general rule is this:  Route the traces as best as you can, but within reason.  Run them as differential pairs, but don't worry too much about matching trace lengths exactly.  Take care of them, but don't stress over it either.  

I have done this on many Gig-E boards and have never had issues.