If you want to use mobile site send the link to your mobile now. I have been using the mobile site for couple of days and took some shots.Click the pictures to enlarge them for better view.
The advantages of using the Google+ mobile site is that you always have access to Google's other products like web, Gmail etc. The detailed comparison would be possible when the final Google+ iOS app comes out but for now the mobile site does the job.
Here a look at what the mobile app has to offer when it comes out for iPhone.(Its already out for Android though)
Download the Google+ Android App