Palmetto State (PSA) all the way. They have sales every single day so just keep checking for what you want.
PTAC is their new low-end brand that had some rough bore issues reported (none that affected accuracy that I'm aware of) but they're straightening that out. Those are dirt cheap uppers.
The PSA brand itself mostly have barrels made by FN, chrome-moly, chrome-lined, etc. Just be sure to read the descriptions very carefully.
One of this weekend's specials......http://palmettostatearmory.com/index.php/featured/mid-length-a2-profile-premium-madness-16-cmv-chrome-lined-stripped-upper-without-bcg-or-charging-handle.html I bought the very same upper over a year ago and it is excellent in every way. If you don't want that then they have plenty of others, just don't ever buy one that's not on sale because the next day they'll drop the price.