The ability to block spam without any problems or downtime for our business users was great! We are able to use this product with no issues at all since we have been using it as part of an overall email solution from other providers (such as Office 365). I would like more features but nothing that has come up so far seems too much trouble when you can get them elsewhere already built-in into your existing platform/solution - if there's anything else they could add then please let me know :) Great tool which does exactly what its meant to do very well indeed. Nothing really comes close out here yet anyway :D.