I can vouch for Heartland. A friend and I split a liter. We used to buy from Wizard's before hysteria set in plus their growing pains, I'd say the nic is very comparable in quality...heartland's might even be a bit better. Wasn't real happy with the last we got from Wizards a few months ago, it came with a very slight yellow tint and stronger smell than usual, uncharacteristic for them; it tasted fine though.
Nic keeps a long while packed in glass bottles in the freezer
Nic keeps a long while packed in glass bottles in the freezer