Thanks! Would you happen to know which type of diverter (pull-up or pull-down) makes it easiest to clean mineral deposits? And also which one is easier to replace O-Ring if necessary?

Actually i just found out that Delta 5.25" pull-downs (which reach i want) are plastic, not metal, and that they're notorious for leaks. It's like each time i sigh with relief and think "eureka, i finally figured out which trim set components to get", only to run into more & more curveballs.

You are confusing multiple parts here. Hoses for hand shower are often nylon, which is extremely durable and abrasion resistant. There's not a thing wrong with a good piece of plastic for that, or almost any other part. Delta, Kohler, American Standard, Groehe, and a whole host of brands are all good quality. Yes, even if there is some nylon in them.

This is to what I assume you're referring as pull-up and pull-down shower diverters, on the tub filler spout.

I have a pull-up, the only type on which I have experience. The diaphragm hardened over time which eventually resulted in non-function due to not sealing. Easy DIY replacement of the diverter. I also have unsoftened well water which results in accumulation of mineral deposits which also causes dribbling. I occasionally clean up in the spout with vinegar.

So where did yours dribble from? I'll have to see if there's a vid somewhere showing how one replaces a pull-up diverter.

Note that the pull-down version is supposed to be superior technically-speaking, except they now make some of them out of plastic, so there's been functionality complaints.

All shower divetrers will have a bit of backflow dribble from the pipe to the shower head backflowing after the valve is turned off. The water still in the pipe to the head has to exit somewhere!

Mine dribbles a bit from the spout while the shower is in use, even with the new diverter insert, due to the mineral residue inside the spout preventing the diaphgram from sealing 100%. The shower is fully usable.

I have a hand-held-able showerhead that I leave hanging down off the bracket when not in use. All the residual water in the shower feed pipe fully drains out from both the spout and showerhead when the faucet is turned off.

My family home built in 1964 had a three-handle tub faucet. The middle knob shut off flow to the spout, diverting it up to the shower. There was no dribbling during shower use unless/until such time as the faucet seat for the diverter valve wore out and needed replacement.

The following may help you (that's if the pic you posted is a past pic as it doesn't seem to have a diverter).

From what i could tell, various popular methods are used to clean diverters: (1) Silicone-containing lubes such as WD40 or PAM (2) vinegar/bakeSoda (3) CLR - calcium-lime-rust remover (4) manually scraping away the deposits...

https://www.youtube.com/watch?v=4OjrL09CXrQ

https://www.youtube.com/watch?v=jr5OYuLQ77s

https://www.youtube.com/watch?v=Osm45RXfS9A

https://www.youtube.com/watch?v=YAoRZwcAPc8

https://www.youtube.com/watch?v=iOSLQPzewWA

https://www.youtube.com/watch?v=cElV1PcYIoA

LITTLE BOY (sorta long) - https://www.youtube.com/watch?v=KwSu461A4_M