Our Delta pull down kitchen faucet has always been flaky because of the Diamond cartridge linked here:
https://www.deltafaucet.com/parts-product-detail?modelNumber=RP50587
They only seem to last now 1-2 years at most. Either they leak, drip, or squeak. I called a few months ago to get a replacement cartridge and they said that they will only replace them every 5 years now. And I was on record of 2+ years for my last one. My neighbor just had a new bathroom put in and used Grohe fixtures. Grohe is a family member that started his own company from Hansgrohe. Both German. I decided to give it a try and ordered a Grohe Lady Lux kitchen faucet:
https://www.grohe.us/Single-Hole-Pu...et-Triple-Spray-175-GPM/GROHE-CHROME-32298003
I installed the above about a week ago. First problem is that the spray head drips at times. It holds a lot of water when off and whatever causes it, it decides to siphon. So, you get a slow drip for a few minutes. I have not been able to figure out what triggers it. It is not leaking at the cartridge as the dripping stops over time. Next at low flow the head buzzes. It annoys the wife. I am hard of hearing, so I have to put my ear to the spray head to hear it. Here is a link to the noise:
https://www.dropbox.com/s/muxufwi7g7j6gi1/IMG_4017.MOV?dl=0
I have emailed customer service at Grohe, and am waiting on a response at this point. The good points of the faucet is that it has a really good temperature control. It also produces a water stream that is not aerated, it is crystal clear(maybe that is why it buzzes). Was it worth 400+ dollars. I would say no at this point.