This isn't software to be used for analysis. Sendy is f-in awesome! I've used it for a list of over 25k and it hasn't failed me once. Like others have said, it's not as brain dead as Mailchimp, but I wasn't expecting it to be. The developer is great and it just works(tm). The price is awesome too.
I looked through the source and thought, sure, it's not computer science that was built on the latest "Framework X", but it worked fine. To me it signaled, they we're just getting shit done. God, I'm so over the days of analysis paralysis "proper framework" development (that's for another rant I guess).
Please, pay no mind to the parent post. If you're looking for an alternative to AWeber (I'm not saying it's got as many features as Aweber) or Mailchimp, then Sendy is awesome.
I've been hosting mine on a Digital Ocean 1GB server for about 7 months and it's worked flawlessly. Their 2.0 upgrade went without a hitch. Couldn't recommend this app more.