If the price difference between the Zojirushi and Panasonic is not much, I would go with the Zojirushi. I've never seen a bad consumer review for either brand.
As for features, both simple glass-lidded designs and more complex locking lid designs can work equally well. All of the Panasonic and Zojirushi commercial designs have non-stick cooking pots and keep-warm functions. Most importantly, they'll make a perfect pot of rice consistently, once you get the water/rice proportion right, which is what you really want of any rice cooker.
Panasonic's cookers carry a 6-month warranty, and Zojirushi's have a 12-month warranty. I can personally say I've abused my Panasonic for 10 months, and it still works great.