If you are talking about a 16" lightweight barrel, the other option is a bushmaster, which will be chrome lined, otherwise I don't know much about Model one uppers since I don't have one. I have seen pics here and there and they look okay, I would cough up the extra dough for a Bushmaster, unless you are on a real tight budget, then a Model One is better than holding the lower up to your shoulder and yelling BANG! Actually I don't remember hearing anything bad about their uppers but have not paid  close attention.

Old Painleess has one of those Model One uppers and he's a pretty sharp guy. If you e-mail him or IM him when he is on the board he might tell you what he thinks, he's a former LEO, has been to Thunder Ranch and is a trustworthy guy, I bet he'd tell you to save some bucks and get it, though I think the chrome lining is worth the extra money.