We got one, and just started using it. I'd say that it's probably not necessary, although it does help for spraying vegetables from an angle.

I have the same pull down faucet on both our sinks and use all the features as much at the prep sink as at the main sink. I like having the spray feature on while I wash and scrape veggies. I like using it to clean out the sink. And I think the water tastes better when the spray is on since it gets aerated. Luckily, this is something relatively easy to change out down the road....if your budget is too tight now for 2 pull downs you could get one later on if you decide you want it.

Also, I don't know if this is unique to my faucet but the water comes out faster when the spray is on. It takes a lot longer to fill a pot in stream mode.

We put in a smaller faucet at the prep sink withthe larger one withthe pull down at the main sink. We'll be replacing the prep sink faucet. We say that's our one mistake, but it was the right look and was on clearance, so it was one of the less expensive mistakes we could have made -- and an easy one to change.

You can do better -- if you will be prepping at your sink, get a sprayer of some sort. It will help you rinse veggies, rice and other things.

You definitely want a faucet that can swivel out of the way. If you get a pull down or pull out faucet, you don't even have to put a pot in the sink to fill it. Our KWC Domo has a button to tap to keep the spray on, hands free. Being able to pull the faucet out makes it easier to spray scraps into the disposal. We also like using a grid.

I got a pull down for my food prep sink. It's a slightly scaled down faucet than the one I got for my primary sink. It's the Kohler Simplice and comes in two sizes, one for primary and one for prep sinks.

I have a pull down (not out) on my 15" round prep sink. I use it all the time to clean the sink, fill pots that are sitting on the counter, fill coffeemaker, watering pitcher. I use it much more than the pull down on my cleanup sink.

We have a pull down faucet in our main sink (Kohler Vinnata) but we are putting in a pull out faucet on our prep sink (Kohler Fairfax). Our prep sink is in a corner w/cabinets above on the left and seating at the peninsula on the right. The smaller profile faucet will (1) take up less space on the peninsula, (2) not compete w/the cabinets above, and (3) reduce splashing of people sitting at the peninsula...but I will still have the ability to have a spray and to take it out to direct the spray wherever I want it.

Pull out faucets are usually less expensive than pull downs.

HTH!

We intend to put a disposal in the main clean-up sink but not in the prep sink. I bought the basket strainer thinking to capture any waste for the compost bin. We were told small stuff that doesn't need grinding goes down all the same either way.
Now I'm wondering what happens to all those extra coffee grinds, for example, that get rinsed through. Will that clog up the works? Is it foolish not to install the disposal here too? Thanks for any opinion you may have on this subject.