I've an Android, just using the Calender linked with Google so it transfers back to Outlook.
Any daytimer app shouldwork well.
What I'd like is an app that lets me take a phone call with call display and schedule an appointment directly without having to re "type" the number and name.
There ain't one. The type of product is wide open. In my neck of the woods I was quoted $5k minimum to write an app like that. Probably be way over that after all the changes and edits. Have to sell it to bunch of service providers just to break even.
The calendar on the phone works just fine. You can set it up to sync with google calendar through the google synching service. We were using it with both of our droids, blackberry's before that and my wife got the 4s in October. It took a little figuring but we were able to get the iphone to sync and schedule appointments so that both of our phones can enter appointments and it shows up on both phones. Or you can schedule online through a pc. You just need to setup a google calendar for each person who needs to schedule and then allow them to recieve and be able to change calendar information from eachother.
google calender kinda works. I am currently trying to use it so I can get away from carrying a schedule book with me. its too bad the color coded events can't also show in your phone like they do in google calender. it would be nice if one day you could hit a button and the customers voice could be used to go into the calender. that way when your talking on the phone it could take the info down automatically.