I'm with you guys. I lived overseas when I signed up for Grand Central, which became Google Voice, so I could get a US number for my mom to call me on, that I would route to a skype number (it's harder to keep the same skype dial-in number if you're as forgetful as me at keeping a balance on it).
Now I have Google Voice going to an app on an old iPhone with no cell service, and use WiFi for 99% of my calls, occasionally sending the traffic to any number of 'burner' phones if I won't be near WiFi.
The funny thing is I had never noticed the MMS issue.
When I'm at the computer, I use the Hangouts plugin for chrome to make and receive calls and it works well, where before I had to be logged into the right Gmail account and have the page open for it to ring. If you use Chrome, I highly recommend it.