The replacement cartridge Delta is shipping to me will be the third cartridge in this faucet in only 27 months.  After running hot water exclusively, it won't shut off completely and drips for several minutes before I can finally completely close the valve.  I hope the quality has improved.  It's also nearly impossible to find the "sweet spot" for warm water.  It's either hot or cold.  When this replacement cartridge begins to leak, and I know it will, that's when the entire faucet will be replaced.