I've been on Sendfox for about a month now, moving an 8.5K list from Mailchimp. Migration was reasonably painless, though transferring my automation was a manual "cut and paste" process and took some time (it's a long automation). "Deliverability" of emails has been as-good-or-slightly-better-than MC even without the "Empire" add-on. I used the standard Sendfox template on an email and asked my subscribers how they liked it and got an overwhelmingly positive reaction. I do wish I could make a few tweaks to the template and save it as my own but I don't see a way to do that.

I did run into one glitch (a 'resend to non-opens' went to the entire list instead) but Support was responsive and it got take care of.

I don't need/use all the "bells and whistles" of Mailchimp. I find Sendfox an excellent and far lower cost alternative.