I've switched completely to using iCloud services (including mail) over Google services. All-in-all, iCloud has been great for me. All the iCloud-enabled apps work well and work together well on my MBP, iPhone, and iPad. The Apple client(s) all work very well (Mail, Notes, Reminders, iCal, ...) and I even tie it into my Outlook at work for mail and calendar syncing to my work Windows machine. I haven't run into any reliability issues with iCloud as of yet...everything seems to run smoothly. I also like my iCloud address better than my gmail one
It isn't all perfect though, I do miss some Google features and benefits...gmail's web interface is worlds better than iCloud mail IMHO. I also miss a few gmail features (labels, great spam filters, multiple addresses, etc.) which tempt me to switch back from time to time (at least for mail). Google calendars work well too and are easier to integrate with my work setup using googlecalendarsync (for the record, I use CodeTwo Sync for iCloud now and it works well). iCloud doesn't sync read status between devices, so you can read new messages on your iPhone and your iPad will still be badged as having the same new messages (and Notification Center)...annoying, but not dire. Sharing gcals "seems" easier since more people seem to use gmail. so sharing with them is already setup and doesn't require an Apple device (to create an iCloud account). Space is cheaper/free-er at Google too, but, like you mention in your post, Google services aren't truly free and come at the cost of your privacy.
So, I guess the gist is that it isn't bad, not perfect but not bad. If you only use Apple devices, iCloud works great. If you want (nice) web access and/or heterogeneous device support, Google services might be more the way to go. If you truly only use clients the web site differences won't matter to you. Likewise you don't (likely) use multiple labels on messages, rather treat them like folders anyway so that particular feature isn't important.
I'd suggest using them both for a bit and see how you like it. Both services work well with your devices, just a matter of needed features and/or opinion I guess.