We are using OpenEMM for about 3 years and are very happy with it. We'll upgrade to 2013 in two weeks.
I believe that OpenEMM is the right choise for you too.
- Web forms for capturing leads
Yes you can easily create your own webforms. See one of our forms as example, where we display an OpenEMM Webform inside an iFrame of one of our sides:http://www.galaxy-software.de/newsletter
- Single Opt-In
SOI / DOI are no problem.
- Autoresponse / Follow-up emails (event based)
Time / Date / Action based follow up mailings are no problem
- Campaign management
Although we don't use this feature, it is included.
- Notification of new leads
You could implement a feature for this.
- A/B Split testing if possible
The automatic A/B testing is not included in OpenEMM, but only in the EMM Manager, the pay-for solution from Agnitas.
However, you could create target groups and do manual A/B testing.
- Customisable unsubscribe links
No problem. See one of our unsubscription sides as example:http://dadagoo.com:8080/form.do?agnCI=1&agnFN=reg_gs_abmelden
The unsubscribe feature in this demo link does not work, so that no one gets unsubscribed
- No "Powered By" buttons etc.
There is no such button or message.