So far Acumbamail is a good solid product. There are some good and bad points I'll try to list.

BAD :
- still missing essential integrations such as Latest Post Campaigns.
- missing WWW widely used languages such as French
- navigation can be very complex
- finding menus (such as "Content Sources") can be very confusing, and you have to navigate to the farthest hidden place of your project to find a link to add some functions
- impossible to use your own SMTP service (forces you to use theirs)
- editing Email / Campaign templates can be very confusing (they keep on duplicating for some reason...)
- Integrations with automation services such as SureTriggers are too thin : we need many more options

GOOD :
- it works
- quite a lot of options & services (Email, SMS, campaigns, websites, surveys, ...)
- deliverability is ok so far, and quite quick ( < 2 min)
- vast Template library (but a little too "marketing", not enough classic/elegant designs)