3 - have owned one, one of which said he AND friends have had threads strip, (that's at least 3 then)
AFAIK, some of the older series Windy casings did strip - in particular, an MT-PRO1300 Legend I had back in 2004. This issue seems resolved since Windy started using a different aluminum alloy. I know none of the several new casings I've had since 2008 have had any problems, a fact attested to also by my friends who have a similar model (i.e.ZR3000 series).

Anyway, I believe no one here is forcing anyone to buy a Windy case - to each his/her own. Speaking for myself, all the casings mentioned so far (and Windy) are available where I'm at, and I choose Windy...

..and Abee for that matter!

HTH.