Emoni,
Your evaluation of JET is a bit off.
Almost always subsidized living assistance
Nope. Sometimes, yes, but not almost always.
Health insurance subsidized sometimes
Nope. Always.
Government program, opens you up to other opportunities.
Well, yes, any job here does that. Doesn't have to be a government-sponsored one.
As for non-JET jobs:
General choice of living region
Yes, but if you go with the employers who hire the most teachers (the big 4 eikaiwas), you have little choice.
Specifics on position prior to leaving
You get these with JET, too. Just what specifics are you talking about, though?
More experience required
More difficult to get the position and experience often required.
Where did you get this? Eikaiwas usually require a bachelor's degree in anything, and nothing more.
Harvey,
You must've seen some rare JETs. Most that I see do nothing but complain about the down time and many other things.