I'm starting an E-Card business. And although mine is completely legitimite, I know they can be frequently flagged as spam.
These are for people's birthdays and such, and it is important that they have the best chance of reaching the recipient.
Am I better off using Google mx servers for my mail? Or is there a service that could help with this? My host is in good standing with the big guys, but they are getting bigger and bigger each day.
I would not recommend using Google's servers. I would instead recommend you use some sort of mail sending service (Postmark and SendGrid come to mind).
If you send via Google you will have the following problems:
I can vouch for PostMark. I have used them and have nothing but great things to say about them.