The long list goes on but here are my top few issues.
1 - Slowest creation of new campaigns ever once you submit it to FB to start (So if you need to change something or add more ads you can't until it posts sometimes hours later)
2 - Can't create new ads once a campaign is set up. (Have to clone existing ad limiting your ad options)
3 - Can't create new ad sets once a campaign is set up. (Have to clone existing ad sets limiting your ad options)
4 - Can't use their super cool matrix ad builder (only once when setting up your first ad) the matrix build multiple ad variations fast by multiplying headlines, photos and descriptions you ads to make a lot of ads all at once.
5 - Support seems incapable of understanding your issues and calks it all up to it just is how it is.
6 - All the best dashboards are at the campaign level and not at the account level
7 - If a another agency has used their tool you can't use it with that client until you go through some process with Ad Espresso to get them to clear it for you.
8 - If you buy their yearly subscription and have tried to work through your issues with support they still will not refund anything period after 30 days. I was working on issues with them for months. But some how it is all my fault so I must pay for a product I can't use.
9 - Only after tying to cancel do they claim any of your support tickets will were added to future software updates of the company. But since I don't get paid to find their bugs I could care less. Review collected by and hosted on G2.com.