First impressions:
Having tried 3-4 cold email platforms this seems very intuitive and well designed. It also features a bulk upload email accounts tool via CSV which will make my life much easier.
The limits are great. To be able to send 20k emails monthly, you need 13.3 accounts firing away on full speed (50 emails per day). Multiple workspaces!!!! and no need to delete and upload data every week or so as you can keep all your contacts there and only pay for the unique contacts emailed per month. Kudos on thinking the plan through, I think this will become a favorite on AppSumo!
The only minus is the sample email verification which really you should use something else instead first as that number is not sustainable (it is one use credits). I'd rather it wasn't mentioned so that nobody gets the wrong idea, but perhaps useful for those getting started and wanting to use it for a small test batch.

Will test fully and come back to change this if anything doesn't add up!