Our company (B2B, a SaaS without a static billing model) has used Zoho for a few years, mostly as an outgrowth of the use of CRM. None of the apps are the best in breed, but the price is great, and it's more than adequate for small companies like ours. Many alternate solutions are far too complex, as they're trying to capture more enterprise customers.
That said, we do use still Google for Gmail and Drive.
That said, we do use still Google for Gmail and Drive.