I think the main problem is the rubbish bleeding process..
The fact the kit costs 1/3 of the brake set if you have elixir 1’s doesn’t make them cost effective.
I have been running mine for a year and a half, and other getting past the most aggravating bleed process they work fine and are nice and powerful used year round.
The bleed process though.. many a time i have bled as per the instructions and then you find the lever could feel better but works..
So you bleed it again and the lever then feels worse.
Then you do it again and the hose on one of the syringes fails and your back to square one..
Which could be a good reason why there is air in there because its all or nothing with the bleed process.
What has redeemed them from the bin due to the rubbish bleeding process. Was only using one syringe and a rag at the lever end, and pushed the fluid out that way retaining the same bleed procedure.
And just remembering, when i got mine new the hose was to short so bought a new hose, and was surprised with the contaminants which came out of the fluid for new brakes.. That’s not going to help longevity.