Your rip times are comparable to mine, the one hour example I gave was a for a one hour black and white TV show. I wondered if the CD drive was the bottleneck (I was using the internal drive on the 2008 MBP) so I got a fast external DVD drive (a big ugly monster). Didn't make any difference.
Out of 1200 commercial DVD's, I only had a handful that wouldn't rip - less than 20. I tried MacX DVD and another program and they couldn't do the problem DVD's either. Finally, I just purchased the few of these that I actually wanted from iTunes. Anyway, I saw no reason why I should switch from Handbrake - it works really well and it's free. Now this might have to do with the type of DVD's you're ripping, very few of mine were recent "blockbuster" movies.
Try ripping a couple on your 2012 MBP - I think you will find a big speed difference. I connected my machines with ethernet and used filesharing to transfer the ripped movies - easy. I don't use USB 2.0 disks anymore, they are just too slow for me.
See the link to the article in my post that you quoted. It will tell you everything you need to know about putting your library on an external drive or moving it to another machine. If you use an external drive, I strongly suggest that you move the iTunes
database to that drive as well as your media - this is covered in that article. Otherwise, the database will be stored on the internal drive on the computer. Problem is, if you happen to start iTunes and the external drive is not available, your database can get corrupted. This is a real mess - happened to me and was a pain to fix.