-> > All transformers are not created equal.  Neon Sign transfromers and
-> > Oil Burner ignition transformers are designed for arc/spark duty
-> > (quasi short circuit).
-> >
-> > Microwave oven transformers are not.

This is true but, with external current limiting, several microwave
oven transformers may be wired in series to build a Tesla power

-> I know that neon sign xformers are buit with a magnetic shunt to
-> limit the current during a short-circuit condition and that micro-
-> wave oven xformers aren't, but what other differences are there and
-> how would they affect their use in Tesla coil circuits?

Not many, they tend to be lower in voltage, so they need to be ganged up
in series banks with current limiting on the primaries. Plate type
transformers may be treated in the same fashion.

-> I wired two 4kV microwave oven xformers in series to give 8kV out,
-> an (if my meter was correct) I was pulling over 60 A from the wall
-> (on a A breaker!) when I was drawing an arc! Obviously, to use a
-> microwave oven xformer you need external current limiting (like
-> the larger pole and potential xformers), and you can saturate the
-> core and heat thing up if you try to draw too much current, but I
-> assumed they would work fine if you limit the current and don't
-> drive them too hard?

You assume correctly.