they are definitely fine, especially if you're not carbonating in them.
personally, i ignore all the nay sayers and i naturally carbonate in growlers all the time and have never had one explode.
I do use polyseal 38 mm caps http://www.benshomebrew.com/ProductD...uctCode=eq38mm
which create a better seal than the single use caps growlers usually come with.
You must love this country more than I love a cold beer on a hot Christmas morning. - Homer S.
And how is education supposed to make me feel smarter? Besides, every time I learn something new, it pushes some old stuff out of my brain. Remember when I took that home winemaking course, and I forgot how to drive?- Homer S.