I need to send emails from my social service (this is continuation of Experiences in mailing to registered users). I got strong feeling that it's better to avoid problems with email server configuration and maintance and to choose email provider which will take care of all painful problems.

So several offers were compared: http://imgur.com/JkK2X.jpg

Three of them look very attractive: Postageapp / Sendgrid / CritSend

As alternative i'm considering setup GAE app.

Email provider is quite easy to start work with, but have no idea how much effort require GAE to integrate with PHP.

So my question is: which option is better to choose:

• email provider
• GAE

?

Two factors are important here:

• business background (therefore prices are mentioned),
• work required to setup and maintain desired solution.

Preferably i would love to avoid all email-related problems (like black lists and so on).