As often as I hear people complaining about the Google Calendar, I'm having much more difficulty with Zoho's. Meeting times are in half-hour increments, and there are no settings to change this. I can't schedule my class at 9:10 or 10:40. The calendar can't work in my situation and I've had to move back to Google's calendar.
Not having all the apps in one place is really going to hurt Zoho's interest for me.
On the other hand, Google started offering offline access to the calendar yesterday. I noticed it when I logged in, clicked the link, and was finished. Zoho has offered offline access for its suite for some time, but I'm not clear on which apps that includes. I'll look into it.