Neither. Delta makes a better product, and has better customer service. Delta faucets are usually more expensive than Kohler or Moen faucets.
There is a reason for this...

Fact: if you have a problem with a Delta faucet, which you most likely will not, they will make it right, no questions asked.

Fact: if you need a part for a Delta faucet and cannot wait to get it from Delta, you can find Delta faucet repair parts at just about any hardware store that carries Delta products.

Fact: neither of the above two facts apply to Kohler or Moen faucets.

Kohler and Moen change the internal designs of their faucets as often as they bring out new models. Delta does not change the internal design of their faucets very often. If/when Delta does make a change, one can always find parts for both former and current Delta designs. Good luck finding Kohler and/or Moen parts.

I do not work for Delta, Kohler or Moen and I'm not a plumber. I learned everything stated above the hard (i.e. expensive) way through the process of upgrading and remodeling our home over the past 10 years.

Trust me on this...
Delta good.
Kohler and Moen bad.

Go to your local faucet retailer of choice and select one of each brand of faucet named above. Take each faucet and examine the pieces/parts, specifically, internal working parts. Take note of the materials used, etc. Then, walk down the aisle where spare parts for faucets are displayed and take note of which of the three brands are available. You will find Delta parts. You will not find Kohler or Moen parts.

And in case you were wondering, calling Kohler or Moen will yield the exact same result as looking for a part on the parts aisle... zip, zero, nada.

Now imagine a leaking (Kohler or Moen) faucet...

And one more thing, the Plumbing Department Manager at my local Lowe's also happens to be a retired Master Plumber. The only brand of faucet he will recommend is Delta. Not all Lowe's/Home Depot employees are ignorant.

Regards,
tp