I've had really good luck with these:

Mushkin Enhanced Atom Series USB 3.0 Flash Drive (MKNUFDAM32GB) https://www.amazon.com/dp/B00HFPW114/ref=cm_sw_r_cp_apa_msVTzbGSWP1PY

Two in my NAS in a mirror for boot and one for my esxi host. No dead drives yet for about a year and a half.