Best ear plugs for both sound quality and reduction

+1 I had my audiologist custom fit a pair of Etymotic Custom Musicians Earplugs with three attenuator options for different applications. I believe the 15db, mid attenuation one has the flattest response. I don't believe there is a better option out there.

Etymotic Custom Musicians Earplugs

Tight band in a smallish club and the sound was clear and clean with excellent overall sound quality. Except it was unbelievably, punched in the chest loud. I survived it using FLARE AUDIO Isolate earplugs. Anyone unprotected must be regretting it. 

I use the Loop Ear Plugs.  They are popular with my concert going friends.  Inexpensive and do the job.  They come with a variety of swappable size adaptors.  Cheers

I used to use Kleenex until I realized the sound in concerts is terrible and too loud and I do not like looking at musicians... I like listening to music, and for rock and amplified concerts it sounds much better at home. I haven't gone to an amplified concert in over fifteen years. 

Like others have mentioned, customed fitted by an audiologist are your best option. I have Westone with three attenuator selections.