In my experience the openrates on Sendfox has been better than encharge for my newsletter. It's a great product for weekly newsletters and just staying in touch. If that's your usecase you can save a lot of money compared to other tools.

The one thing I didn't like was if a user opts out and tries to opt back in on the website they can't. They'll be auto flagged as already unsubscribed. Brought this up with Sendfox and they say that's a <1% use-case and may lead to spam/abuse using their tool (plausible). Still, I would like people that have shown interest and wanted to get back on the mailing list to be able to. I think they may be small use-case but I can't imagine turning away potential customers/clients.