It took me a few years to switch from Yahoo! Mail to Gmail as I patiently waited for Google to get their act together an add the feature allowing you to define the "From:" address as something other than your Gmail account. Yahoo! Mail had this for as long as I can remember, and it kept me as a loyal customer.
Sadly, it turns out that Google Calendar is history repeating itself. The calendar feature is the last and only thing I still rely on Yahoo! for and I'd glady switch to Google in a second if it supplied the features I need. But, alas, it does not. It has two major deficiencies:
1. It doesn't support the recurring schedule of "every other week". Most of the regular events on my calendar repeat in this manner, such as weekends with my daughter. A rather disappointing oversight on their part.
2. Per-event notification configuration. You can have all of your notifications via e-mail, or all via SMS, or both, but you can't have one come by e-mail (like a week early warning of an upcoming birthday) and another come by SMS (like 10 minutes before a meeting). Again, a frustrating limitation.
Slightly related to the latter, but not necessarily a deal killer, is the fact that you can only set notifications for events on your primary calendar. I set up a separate calendar for my company-related events, and another for just birthdays and anniversaries, then realized to my dismay that I couldn't set up notifications for any of them. Thankfully, it's easy to move events from one calendar to another.
Oddly enough, you can set a notification on an event in the primary calendar then move the event to another calendar and the notification icon remains, but I've not tested to see if the notification actually gets sent. That's an ugly hack.
My colleague assures me that they will fix these problems quickly, but based on how incredibly long I had to wait for them to match Yahoo! Mail's feature set, I'm not going to hold my breath.
Oh so close, Google. Oh so close.