I have been using Joomla CMS for 2 years. Before AcyMailing software, I was using Acajoom Pro for one year. AcyMailing Enterprise is an awesome component and 10x better then Acajoom Pro or jNews Pro.
It works very smooth with Joomla registration. It hands all bounces nicely and it shows very nice statistics. The support is extreme great and every time I had a complain (and believe me I had alot of requests and complains) the developer went and change it for me and improved it right away.
Comparing with Acajoom support, which you never speak to a developer and just some representatives, plus you have tons of bugs that came in their new jNews software, I must say that AcyMailing is the way to go.
I usually don't leave feedbacks much, but this is one of the first experience that it was pleasure talking to the support. One of the best components on the market!