Each and every mod you find will have some underlying weak point to consider. Yes, even the venerable Provari. I'll leave that one to its owners to nit pick.
Each also has its strong points.
You simply need to study each mod of interest, read User
reviews<NOT Reviewer
reviews> to see what those points are.
Next decide what you can adapt to and what you can live with/without.
I have (2) eVic's, known for first run issues. Mine have served me flawlessly. Many have been not so lucky.
I have a YJ lavatube - Hits like a hammer - poor low power setting control and Weak 510 threading(still, it works)
4 KTS CCTS Mechanicals - no problems found - some have had switch isues
sigelei Telescope mod $19 - works great - lock ring will screw right off the bottom if not careful - tighten to much and it fires continually
What I am saying is anything can be nit picked. Even in a good production design there can be the occasional faulty piece.
KTS Plus, for an inexpensive mod Performs excellent. As always, minor cleaning/tweaking may be required per individual unit.