If you are really hot to try the ACOG, I'd buy it from a low cost place like Sableco or SWFA and then try it out. The TA31 is made to mount in the carry handle, and other than making the rifle kind of awkward for cases and racks, works well there.
Try it out and see how you like it. If you decide you don't they are popular enough you can probably resell it here; but you will lose money on the deal (a $100 or so). Your other alternative is just to tough it out and try and find someone locally who has one or make it to the Black Rifle meet this year and try one there.
I waited two years before buying my TA11; but I am really happy with it and glad I did the research first.
Edited to add:
Use the [url=http://www.geocities.com/ocular_times/strabscrn.html]cover test[/url] to determine if you have phoria first; because this determines how useful the BAC feature of ACOGs is. Without this, the ACOG is just a cool, rugged, illuminated scope.