I insisted on it for my last cycle which was shared (I was the second recipient). Of 5 tested only 1 was normal = BFN. The other couple did not do testing. They were also a BFN for their fresh transfer. I do not know if they did an FET since then. By the way, this crappy ratio of normal embies is exactly the result I had from my last OE cycle: 5 embies tested, 1 normal = BFN. Back then (2008) I used traditional PGD which tests fewer chromosomes than CGH does.
I would have done CGH this cycle (I was the only recipient) but I couldn't afford the extra expense. Because I didn't test, I transfered 2 blasts and am now 6 weeks along with twins. If I had tested I would have transfered only 1.
Also, I've changed my protocol for this cycle to use a slower introduction of progesterone, based on the results of an endometrial function test I had done by Yale last year.
Best of luck to you.