I dislike G+, but there are some old-school Google products I love.
Google Voice might be at the top of the list.
It's not just that I save over $1000 a year on long distance charges because Google Voice.app lets me call Montreal for free from my AT&T 4S.
It's also that when I travel I configure my Google Voice business and personal numbers to send me email only. Then I forward my mobile and home numbers to my Google Voice . I get all my messages by email when I've got WiFi -- and I don't run up any roaming charges. Tonight, for example, I picked up a message that VISA had locked my card due to international charges (easily fixed, next time I'll call ahead).
It's a great service. I worry that Google is going to drop it -- they don't seem to have a way to make money from it. I wish they'd just start charging me.
 There's a bit of a trick to this. You can't forward from a number that's associated with the GV account -- you just get your voice mail interface. Since I have two GV numbers I can work around that.