The original 2018 buffer tube dosen't have any problems at all, and comes complete with the complete original buffer spring set.
The BCG set is fine and clean. The only problem with it, is that there is a little screw/pin on the side that has started to move slowly, when shooting the replica, therefore the low price. I imaging it would be easy to fix.
-=======-
Price:
Original 2018 buffer tube - 70 EUR
BCG Set - 225 EUR
Shipping:
GLS 30 euros