It's easy to use, it makes our work much simpler by providing us everything we need in one place at any given time which saves me from having to keep searching for things when I'm working online or offline! The support team are very helpful too - quick responses & great knowledge base articles available via their website (which can be useful if there isn't anything specific about how something works).
There aren't many downsides but they could improve some features like adding more fields etc so as not everyone has access all options out off hand e.g phone number field would help people who don’t have email addresses get added into certain groups/lists easier rather than asking them what type o fphone do i want? For example instead just allowing users choose between "email address only" "name's + emails",etc.