Can someone help me get a handle on all this ? I don't really know what Hangouts is ? I pretty much ignored it because it was part of G+, but now it isn't ?
Where does Google Chat fit in this ? Currently I use my GV number as a separate phone number, used on my laptop, not integrated with my cell number much. So I have incoming calls forwarded to Google Chat, not my cell. Chat then rings on my laptop when I have an incoming call.
Does Hangouts replace Chat ?
Also, can I use my Nexus 7 with Hangouts and my GV number to make and receive calls ? Is it going to use my cell minutes even if I'm using my GV number ?
Google Hangouts goal is to merge all the chat stuff into one. You were never forced to use G+ with it but got extra features if you did. However that's no longer the case.
Yes it's worth using Hangouts instead of Google Talk as it does indeed replace Talk. You can make or receive calls in Hangouts by either keeping Gmail or G+ site open (in another tab) or use the Hangouts extension in Chrome which will work just like a Desktop program.
Yes you can use your Nexus 7 with Hangouts and no this doesn't use Cell minutes which neither does using it on your PC.
It also won't on your Phone if you use Hangouts over Wifi or if your Cell has enough data too.
If your Phone isn't Android or iOS and you have data with has a basic browser you can use the mobile G-Voice site to place Calls over Cell line (will use minutes) and Texts (over data connection or over SMS Cell service):
https://www.google.com/voice/m
Google Hangouts offers G-Voice calling out and you can enable Calling in which is in the settings on Android & iOS.
You can send and receive texts in Hangouts with G-Voice instead of through the G-Voice app / site and now MMS messages (Pictures and such).
You also can get G-Voice Voicemails in Hangouts now too.
Another awesome feature of Hangouts is you can video chat with up to 10 people at once or audio if some don't use a Cam.

However another cool feature is you can even add phone contacts in the Hangout too.
Google Voice does support 3 way calling too. Plus a wealth of other features.
You can even get a Obihai box in your House and hook a Landline phone to it and have a free Landline over your net connection too.
