I like that you can see how much your ads are performing in real time - it's not just some vague number somewhere! It is very easy to set up campaigns with multiple target audiences or devices/channels as well as targeting specific keywords or phrases. The reporting options could be better if they were more granular (eg, by day vs week). Also, sometimes when adding new targets there will be an error message about "duplicate value". This seems to happen regardless of whether we have any existing data associated with these values so this isn't really helpful info at all. We've been using delta since our client switched from Google AdWords over 2 years ago and haven't had many issues while trying out different things here & there. Our clients love being able to run reports showing them exactly what has worked best for us each month.