Stay with brand names, don't buy loose parts from a bin at a gun show.
I have a similar question. Does anybody know if the DD trigger (2-DD21007 - AR-15 Daniel Defense Lower Parts Kit LPK With MagPul Trigger Guard)is actually any smooter than a standard PSA or equivalent trigger?
If it is, I think it would be well worth the $30+ extra to avoid purchasing a drop-in later.
If not, are there any inexpensive lower parts kits w/ that tend to have good triggers from the start?
From what I've gathered from here and ar15.com. What is the rifles intended purpose, will help to better answer that. What are your plans for it?