Love white castle (though the nearest one is 5 hours away) but haven't tried the frozen ones for fear it will turn me off forever. Too many products lose 'body' during the freezing and packaging process.
Frozens are not that bad. Just be sure to add a few drops of water and wrap in foil while heating.
If you google "secret recipes" or whatever, there's a recipe for white castle burgers.
I made them once and they were really good. Hmm on second thought...maybe they don't taste like the real thing... ;^)
I'm in Maryland so the nearest in Ohio or Jersey, so the frozen ones are all I can get. Straight from the freezer, take it out of the plastic bag, wrap in in a paper towel and microwave on high for about 45 seconds. It ain't the same as fresh off the gridle at 3 AM with your mind in an altered state, but it ain't bad.