The positives now outweigh the negatives, from a production standpoint. A bunch of you have been using lead screws now, a few since day one. None of you have complained about the need to constantly replace the brass nut so I feel they must last long enough to not worry too much about it as a consumable part. A vast majority do not have any issue with the allthread and can easily save some money by using the easier and cheap to source allthread.
Cheap leadscrews still bend or come bent, accuracy has a price. Lead Screws with a certified straightness cost about as much as the full kit.
I am still very careful not to say this is the best way, just the way I chose to sell future kits. I have written a fairly long post about this. Ballscrews are still the correct way to do this, allthread is the easiest, leadscrews are the sweet spot in the middle.