The team at perp are very helpful to take your campaigns through their paces until they get just right! They have helped me with different ad formats (amp). It's not always clear what you're supposed be doing when looking over someone elses code so it can sometimes feel like there isn't anyone else who has looked after them properly in house - but I've been really happy working closely along side this amazing group! There was nothing that we disliked about our partnership or experience as clients :D Their support staff were excellent throughout my contract period too which made things easier than ever beforehand!! As far as problems go i don;t think anything came up often enough during either engagement phase where issues would prevent us from getting started again soon afterwards... Our goals changed slightly mid way into each project because changes occurred within amazon themselves e.g., new products being added etc.. This meant some work had already.