Looks like you already made your decision, but in case you haven't, here's another +1 for CMMG. I have 2 of their lowers, one on a 18" LaRue Stealth upper and one on a CMMG upper. Both perform great, not probs at all. I bought the 2nd upper while CMMG was in the mist of some order fulfillment issues, I got it from MI on sale, in stock and it worked out to be a pretty decent deal. From the sounds of it, the CMMG issues are in the past, but check wait times if you order one.
Link to MII went with a 14.5" middy with MI rails on it & I love it. Just long enough to get me to the 16" I need to be legal here in Michigan, but not as long, and heavy as my 18"
If I could do it again, I'll look at AIM as mentioned it a post above, due to there shipping fee (0.01 of CMMG) and their fast shipping.
As for ones to stay away from, you heard who to avoid. Most manufacturers are good, some are better and very few suck. On uppers, you get what you pay for, but on lowers, there is little difference in the majority of them so know what you are looking for and shop for a bargain as long as it doesn't say Blackthorn/Hess/Vulcan or whatever their new name is...
If you haven't seen this yet, it's a good read. It's a year old, but a lot of good info...
LinkBTW, I had a LMT as you mention in your post, but sold it, Wish I didn't. They are nice and the guy I sold it to in the EE said it's the best shooting upper he has ever had...
I should have kept it, I should have kept it, I should have kept it...
Good Luck and don't really worry about what you get for this first build, the second will be just around the corner, trust me and everyone ease that has caught the BRD.