I guess it depends on what you value and how you would like to use them... eg. fly on a Y reward ticket, but fly more often for a given number of points, or fly on a J reward, but less frequently - if that makes sense?
I base the decisions around points (eg CC sign ups, etc) against J rewards to Europe with EY. Mrs D-H and I have taken about 7 legs over the last 2 years and always found the flights to be excellent - in-flight catering, service & seat design better than J with EK in our opinion. So, to put that in context, approx cost of a J return flight MEL-LHR is around $6,500rtn if you book well out (as you'll have to to get J reward seats), or 250,000 points plus about $400 in taxes total on a redemption with Virgin/Etihad.
Whether a a J flight should be valued at $6,500 is another matter of course, but leaving that to one side for the moment your 250,000 points buy you $6,100 worth of travel, with Lounge access (very nice at LHR, excellent if you can get in to the Flounge at AUH, & SYD is to be experienced!), priority everything and chauffeurs at both ends as added bonuses. So I guess that's around 2.5c/point.
If you travel in Y, the cost is about $2,200, taxes broadly similar so you get $1,800 worth for your 125,000 points - or about 1.5c/point. Still not bad, and of course, you get to travel twice as often on your points. But in whY! ;-)
Hope that helps...
Cheers,
D-H