How much of difference between the two,besides the Absolute being 1000 and Nirvana is 1500, is there a noticeable amount of hook

For me the main difference in the two is the reaction on the lane.  My original Nirvana rolls up pretty early and is smooth all the way through the lane, where as the Absolute pushes a little further and starts up in the mid lane and continues from there. 
On medium sport patterns I see a little more hook for the Absolute and on heavy oil I see the same amount, but different looks as stated before

Brunswick Absolute Nirvana
Just drilled up this ball. I put a 50 X 4 3/4 X 35 layout in it. My ball speed is 16.5 mph. Rev rate around 325 rpms. ABSOLUTELY LOVE THIS BALL! 
I have used it in two different PBA Patterns, BEAR and Chameleon. Reads the mid a bit harder / earlier than the Nirvana and still continues on the back end. On BEAR I played 12 - 6 for about 3 games then balled down to the Nirvana. ON Chameleon, I was able to play up 4-5 and get the ball to read some before the end of the pattern and destroy the rack. Really reads the mids and has a larger arc shape. Have mine at 1000 grit. And worked very well. So if your looking for a new ball to start the new fall season the Brunswick Absolute Nirvana is the ball.