I've avoided MSG after an unfortunate experience at a Chinese buffet many years back, but honestly I have no idea what caused my reaction. But after making a batch of mushroom ketchup this week I'd have to say I'm an umami fan overall.
I'd say the points made at the end are valid: MSG is likely the difference between eating something balanced and regulated, and mainlining it. Just as with sugar, how you consume it could well make the difference. But I dunno.