I like that they are able to create campaigns for us so we don't have to worry about it too much.
Sometimes you can get stuck in an endless loop of editing your campaign after clicking "next" or something similar but this isn't always the case when using them! They also do not provide any support beyond what's listed online which was frustrating at first because there were some things my team had questions/concerns about as well (like how many views does one need before being eligible for ad credits). We used teesters services primarily during our launch phase where we needed content quickly - both from influencers and users alike. Their service has allowed me to scale up very fast without having to spend time worrying about creating all these assets myself.