I can't figure out the sendgrid pricing at all. 10/mo for 40k emails and 80/mo for 100k emails doesn't fit a normal model of reducing price for incremental usage and there's no clear explanation for it.

I use sendgrid, and I thought I was using mailgun, but now after seeing the pricing simplicity and ease I'm feeling like I should make the switch.

What reason would I rationally have at the <100k emails level for staying with sendgrid?

Additionally, for the lite plan with sendgrid, they don't include email open and click tracking (even though they DO for the FREE tiers).

Would love an explanation for why this is sensible.