Pepipost

i am early adopters when pepipost serve global customer,
pricing is very unique, we only pay the unopened email.
open email is free. its very interesting pricing.

nowadays, adding domain name in theirs system become more difficult,
maybe i still in free tier, but they have very stricht and maybe high standard about domain name. and every domain is manually checked by their support. it takes time

The prices seemed really good! Was excited to try them out and compare them to some of the bigger providers

You cannot try them out until you do a verification of your domain, this includes SPF and DKIM, you must also have a live website and not use the service for unsubscribed emails (makes sense).
However verification takes 24 hours on average, to top it off you wont get clear answers on why you are denied and basically go back and forth between their verification team who replies every 24 hours.
In the end I was rejected due to my business type (a software company with a multi-tenant environment). I'm not sure on all the details on why this is a problem because I only got a 2 sentence reply with no further explanation.
Overall I invested probably a solid 6-8 hours into this, and delayed my development team from looking at other integrations. Not sure how much time value was wasted here but enough to leave a sour taste in my mouth.
Basically if you signup, just know you might get rejected and waste a good amount of your time. At the end of the day we'll be going with a larger provider, they may cost more but honestly its worth it to avoid the stress.

Advice to management- there has got to be a better way to do things. Learn from the big guys, change your processes. You'll have happier clients and more free time for your support team.

Great Pricing much better than competition
Even Great Support. Support is always prompt.
Very easy to integrate.

You could have multiple passwords to used in different places but thats ok.
Require some readymade plugins