I love that it's easy to use, has great support (even when you're not using them), can be used with multiple plugins at once without conflict or issue. The UI could definitely look more modern/polished but there are plenty of options out there if you want something custom designed - just search around! We've been able to integrate our mailing list into one place instead of having two different tools doing their own thing. This allows us to have better control over who gets what messages as well as being in closer contact wtih those we communicate regularly than before. It makes sending newsletters much easier too because everything about my emails looks exactly how they should. Having all communication from clients go through this tool saves time by eliminating manual entry errors which leads to less frustration for everyone involved.