I gave Zoho a compliment, not sure why there is so much defensiveness.
You are right - open source requires more work. My response related to open source was responding to the article's tone that it was surprising that anything could be cheaper than Google or Microsoft :) Which is silly.
Good point. I have been up way too long. I re-read the question now as just wanting alternatives.
I read the question earlier about email deliverability and black list management as being rhetorical in that those services are usually performed by a centralized service provider.
Glad someone was able to respond with some examples.
You are right - open source requires more work. My response related to open source was responding to the article's tone that it was surprising that anything could be cheaper than Google or Microsoft :) Which is silly.