Acumbamail
Easy to set up (I am basic though)
Nice mature UI, onboarding was simple, setup was a breeze. I a have some email experience so caveat there. Deliverability has worked from my testing. Will keep.
lairdminty
Purchased from: AppSumo.com
Nice mature UI, onboarding was simple, setup was a breeze. I a have some email experience so caveat there. Deliverability has worked from my testing. Will keep.