Just about 2 years ago (give or take a few days), I evaluated Google+ hosted comments, based on moderation / notification options.
A few changes have been made to Blogger - and to Google+ - since then. Some changes affect usefulness of Google+ hosted comments, in Blogger blogs.
I guess to honestly evaluate Google+ hosted comments, I should decide whether to leave this blog using Blogger hosted comments - or move forward.
Periodically, I muse about changing this blog, to use Google+ hosted comments.
I think the decision, of Blogger hosted comments vs Google+ hosted comments, comes down to choice. And, what content and features do you get with one, that you do not get with the other.
Choices for control of content.
With Blogger hosted comments, you can choose comment authentication, comment form location, moderation, and notification. All of these choices give you tools to control comments, in your blog - before, or after, they are published.
Google+ hosted comments give you one choice - comment form location. Everybody authenticates using a Google+ account. Blog owners do not choose commenters, or readers, based on authentication - and have no choices for moderation, or notification.
Choices for distribution of content.
Blogger hosted comments give you a wide complement of subscription choices - using either email or newsfeeds. Google+ hosted comments have neither.
Google+ does give marginally more choice for private blogs - or at least private content distribution - though many options may not involve publishing a Blogger blog.
Control of comments, and of readers.
Google+ hosted comments use community based moderation. You have no control over comments, posted to your blog, more than any other reader of the blog (who can see the comments).
You cannot moderate comments, so you have no need for moderation email. You are notified of comments - but notification relates to who is publishing comments (and you see all of their comments, against your blog and any others targeted by those who you follow), instead of helping you monitor everybody publishing comments against your blog.
Ability to view existing comments.
You can either display Blogger hosted comments - or Google+ hosted comments - on your blog. If you choose Blogger hosted comments, you can view comments on the blog, on your dashboard, and in your email, And you can view any Google+ hosted comments, published by anybody who you follow, in your Google+ stream.
If you choose Google+ hosted comments, you can view Google+ hosted comments on your blog, published by anybody who you follow - or in your Google+ stream. You won't be able to view Blogger comments, period, Old Blogger hosted comments are gone - and there won't be any new Blogger hosted comments.
Reader community commenting options.
With Blogger hosted comments, you can have readers who can comment using Blogger (onto the blog) - and other readers who can comment using Google+ (into their and your streams), With Google+ hosted comments, you'll have only readers who can comment, using Google+.
Comments based newsfeed.
With Blogger hosted comments, you have a Blogger comments newsfeed - and some comments published into the Google+ stream. With Google+ hosted comments, you have only the Google+ stream.
Visibility of comments.
With Blogger hosted comments, you can see all Blogger hosted comments, related to the blog, on the blog, in your dashboard, and in your email (when setup). You can also see Google+ hosted comments, from people who you follow, in your Google+ stream,
With Google+ hosted comments, you can see Google+ hosted comments, from people who you follow and who follow you, in your Google+ stream. You can't see existing Blogger hosted comments - and you won't get any new Blogger hosted comments. The visibility issue causes some confusion, from time to time.
Private content distribution.
With Blogger blogs and Blogger hosted comments, and considering recent private blog access changes, private content distribution is somewhat limited - for large groups of people. Google+ - and Google+ hosted comments - will support groups of unlimited size.
The bottom line.
So having reasoned all of that out, I still see no advantage of using Google+ hosted comments, exclusively, in this blog. People who publish private blogs, with large reader populations, may see things differently.
Maybe given another 2 years, we'll look again.
An Important Update
If you did not use a Blogger / Google account when you Followed this blog, years ago, you are probably not Following now . During the past...