A FlyerTalk Posting Legend
Join Date: Sep 2002
Location: LAX/TPE
Programs: United 1K, JAL Sapphire, SPG Lifetime Platinum, National Executive Elite, Hertz PC, Avis PC
Posts: 42,216
I've been using my Japan Panasonic rice cooker in California without any issue for over a year - in fact, the transformer plug I bought for it wouldn't even let it turn on, so I ditched the step down plug and just use it direct.
The only appliances I know for sure that will have problems are things like hair dryers, curling irons, etc - low tech heating devices that could overheat, create a shock hazard or burn out due to mishandling the extra voltage.