Do you have one of the pull out kitchen faucet? You know the ones
that
have the hand spray unit built into the faucet and it acts as both.

Do you like it? Do you not like it? Why?

I have seen them but never seen one working. I take it that left in
place it functions as a traditional faucet. They seem to have a built in
valve so it can be turned on or off when being held and used as a spray
unit. Do the buttons turn it spray off when depressed or does the water
shut off when you remove and and you press the button to turn it on or is
there some other arrangement?

I've had Moen units. The ones with the in-handle filter are crap. The
plastic connection for the hose is poorly designed and breaks far too
easily. The fact that they'll send out free replacements tells you
something.

I replaced one with a reasonably inexpensive American Standard unit. The
"handle feel" isn't as nice. I have another Grohe unit ($$$) and it's VERY
nice.

Most operate the spray as a switch. Click it and it'll stay. Some remain
switched until switched back manually while others will automatically switch
back to regular flow when it's shut off. Depends on the brand, iirc the
moen switched back automagically.

And if you're replacing an existing hose then use the hole left over for a
soap dispenser. They're a great alternative to people wasting dish soap or
clutter from a soap dish or yet another dispenser. They can be a little
tedious to refill but they're worth it.