I’m looking for a subcompact 9.  The Shield feels best in my hand.  But, I want a thumb safety and the one on the shield seems unusable.  It is flush to the frame and so stiff it can’t be switched on/off as part of the draw.  Does it loosen up?  Is there an aftermarket extension?  Anyone here use it effectively???

FWIW, the Sig365 has a great thumb safety option, but I don’t really care for Sig products.

Check this out on Pistol Forum:

https://pistol-forum.com/showthread.php?51332-Extended-Thumb-Safety-S-amp-W-Shield-2-0&p=1312028&viewfull=1#post1312028

Is there a reason you want to be able to have an option to engage and disengage a safety? I bought mine before they came out with the no safety model. The one I have, I only use the safety when I holster then put back on fire or for some reason have to take it off without it's holster and need to set it down temporarily.

A lot of people complained saying that the safety would come on or off by itself, which is a fishing tale, as it's too stiff and very hard to get at to do such a thing.

My 2.0 has no safety. I'd be totally fine if my 1.0 had no safety either but at the time it didn't exist. Meh. Good luck with your quest but before leaving I would suggest a slimline Glock and put on the Langdon Striker Control Device if you need that piece of mind. Super easy to use.

Why?  Well several related reasons.  My main carry gun is an M&Pc with thumb safety that gives me muscle memory.  Consistency is an issue.

Technically, this is a single action pistol just like a 1911.  Given that fact, I prefer to have a safety.  I know it is drop safe under ideal conditions even without the safety.  However, I can’t always watch my gun all the way into a holster in certain clothing.  I have had clothing snags while reholstering, so I am super careful and a safety is another layer of safety.  When reholstering my M&P I do so with my thumb locking the safety in the on position.  

I have seriously considered a G43x with a SCD, but the SCD for slim lines appears to be out of production.  The Glock angle doesn’t work for me anyway.  The Shield fits my hand like a glove.

Fair enough and it looks like the SCD is still available through that link provided by me but at any rate I understand.

It would be nice if the Shields had similar safeties to the bigger models.  The new M&P Equalizer has similar safeties to the bigger M&Ps.  The grip/frame is still different than the Shields.

Out of luck it happens that my right thumb (last joint) sits right on that safety.  Moving it to FIRE is easy.  Moving it back to safe takes more effort, but that's okay.

Mine was very stiff when new. A drop of oil and an hour of TV while working it on and off fixed it up just fine. Like someone else said my thumb knuckle hits it just right so it works fine.