I have used cakemail for the last year or so, and it's excellent. Very easy to customize for your business, has many features, and great customer support! Not much really, other than that it solves all of our needs - send out newsletters via email, respond to emails for customers with ease, the contact manager works very well. We haven't been able to find anything negative at this point. It is not cheap though, we currently pay about $20 a month per user (we have four), but it solves all our communication/marketing needs. I like that it's easy for people who don't know how mail works at all! The interface makes sense, but you can customize pretty much everything if needed. It was very helpful in allowing me (a new employee) access so we could start sending out emails without having someone else do them first-hand which saved time as well as money since everyone has been doing this work manually up until now!!