I could write a lot about this, but I'll try to keep it short:
1. Unfortunately, you can only have one account per platform in a workspace at a time. This isn't just bad for agencies, as it's not uncommon for a small business to have multiple advertising accounts on one platform.
2. The user interface may not look very modern, but it is functional, which is most important. There is also an Android app which is very cool!
3. The app keeps asking me to relink my Google account. I'm not sure, but I think that Plai's algorithm can't "work" correctly like this and optimize my ads?! - But that might be a little bug
4. Plai can't do some important things for you, such as setting up advertising accounts with the relevant advertising networks, setting up a pixel, setting up conversions, etc.
Unfortunately, there is no help at all from Plai. That would be desirable since the tool is marketed to beginners from what i've read.
5. You can only create individual campaigns, but not ad groups. This makes structuring accounts and distributing budgets more difficult.
5. I would be happy if I could get some more information about what Plai changes in my campaigns, otherwise it seems that Plai just sets up a campaign and then lets it run. I don't need any tool for that.
6. Important options such as negative keywords, bid strategy, rules, etc. are missing. Plai should learn a few things here from competitors such as Adzooma or Adsbot!
7. Finally, I think it's a pity that the focus on the creation of advertisements was apparently lost in such an early phase and that plai also offers landing pages. This feature is just plain bad and should be quietly deleted in order to focus on creating good ads. I think this is the only way that Plai can gain a place in this growing market in the long term.

In my test, some keywords were already promoted that I don't think are good. In order to change that, I would have to go into the Googel Ads account, which makes the point of Plai somewhat questionable.
Also, most of the quality scores were between 3 and 5, so not very good, and unfortunately I can't see what Plai is tweaking here to improve that. But I keep my feet still for a while.

The idea of a platform that bundles and simplifies marketing efforts across multiple advertising networks is fantastic. I think I'll keep Tier 1 in the hope that there will be some catching up on features here – also to stay on top in this growing market in the long term!