I have just switched to the Panasonic BK-3MCCA12SA eneloop AA 2100. They fit just fine. There is considerable discrepancy in reported time versus real time but I noticed that with the Duracel and Kirkland brand non rechargeable batteries that I was previously using as well.
My findings are this: When it reports around 5:00 left, there is actually about 4 hours. When it shows 4 hours, there is actually about 2 1/2 hours, and when it shows 3 hours, there is actually about an hour left.
I typically note that the full charge reports 8:20 and at the end of the show (roughly four hours later) the unit reports about 6 hours.
By the way I am using the Titanium Smart Fast 16 Bay Ni-MH AA/AAA Battery Charger AC 100-240V + DC Adapters MD-1600L. I am quite happy with it, as well.