The system is easy for us as we are not programmers or IT people - it all just works! We have been able find most of our problems solved by their amazing support team who can be contacted via email directly from within your account dashboard (and they respond!).
Sometimes I feel that my requests take weeks before being addressed but this might also depend upon how busy everyone else in Support Team at MWF end up working during any given week/month etc? There's nothing about which i dislike so far though there could always do with some more features added over time if needed without too much effort / cost involved to implement them ourselves eg; better reporting tools would help me make decisions quickly & easily when sending out campaigns using autoresponder emails where certain messages need triggering sooner than others depending what campaign has worked best previously). Their customer service really helped resolve issues fast once identified rather then waiting days like.