We have used ad smart for our media buying process, it has allowed us to keep track with multiple clients at once which helps in keeping up momentum throughout the year when we are running out of time/money etc. It's very easy to use (and customize if needed), but more importantly I've found nothing about their interface as unhelpful or difficult to navigate than other platforms I've been using previously. You can't do too much wrong! If you're looking specifically for an ad-tech solution then don't look any further - they really deliver what they claim. Our client management system allows us to manage accounts across many different types of advertisers without having several separate systems open simultaneously. This frees up my colleagues' team members who work remotely from me so that we aren't bogged down by managing dozens of account files spread between email inboxes.