As I mentioned elsewhere[0], I've had lots of problems with their Mac uploader. I'd heartily recommend sticking with the web upload until it's updated, or using some third party tool (if you have tons, this might be the best option - web is limited to 200 at a time, not resumable if something goes wrong).
And I have tried uploading, its not convenient at all. I have switched to google+ auto backup cause, I don't care about super high resolution since I am not a photographer and my upload speed sucks, I don't have to worry about manually uploading (though its also possible and very convenient). I just set it and forget it, it works in the background. The UI is very very nice, probably the best out there at the moment.
If flickr continues to make minor tweaks and comes in par with google+ photo looks and if my upload speed ever improves then I might consider moving to flickr. I am still a paid flickr member since 2007.
