That's a bit over the top. Mail chimp is hugely valuable if you are in their target user base. And for non-technical clients, mail chimp is (imo) a massive step up from other mailing list providers.
Details: http://mailchimp.com/pricing/high-volume/
Mailchimp is thus $475.00 per 100K per month ($5700 per year!) That is a lot to spend on just email.
With Sendy + SES it costs me $10 to do a send to our 100,000 users.
Now I could play around with switching plans all the time at MailChimp to try and always minimize my costs, but I don't want to play that game. SES + Sendy keeps my costs linear with the number of emails I send, I don't have to play any games with changing plans, and it is significantly cheaper that MailChimp.
Or, as noted throughout this thread, just use SES (or Mandrill if SES's deliverability scares you, but IMO it shouldn't).