I like how easy was for me as an end user is can create my own rules in order have alerts when using different products or services which are connected with them such us facebook etc.. It's very handy tool if you want control your emails accounts without having some kind restriction by email providers themselves about this matter! Nothing at all so far i dislike nothing but maybe more customizations options could be added? For example creating groups where we send our clients newsletters instead sending single mails per person because there might not fit within one mail limit set up by provider itself would solve problem quite goodly :) Also adding filters option will save time while searching through large amount data sent daily via celerity service since filtering out unwanted info before even opening mailbox window solving hassle issue solved too!!