I recently purchased a 50" GT30B, I'm really impressed by it to be honest. I must warn you there will be a small buzzing sound when brighter images are displayed but the sound varies from set to set and shouldn't be too annoying.
As for 3D, I checked it out in store and was 10x better compared to LED/LCD, with hardly any crosstalk at all, if any.
+1 for the TX-P46GT30B