Pam, with the R foot, make sure you check the box for FLOATING free motion, not the SPRING free motion. I have the same machine, and I had issues with it when I first tried free motion. One of my issues was that I was trying to use the spring feet from my old Viking. I expected them to work, but they didn't. I suspect it had something to do with the automatic presser foot sensor. Another was that I didn't have the foot all the way up. Sounds like that should be obvious, but with this machine, it's easy to think it's up when it's only part way up.
Last time I brought it in to the dealer, she had me try another foot, this one is a spring foot, part number 412 54 17-45. I like it better than the R foot and it works beautifully! My thread doesn't tangle up now and the back looks as good as the front. Oh, set the fabric sensor to C, that seems to help as well.
I think a lot of the issues I've read about with the 830 are due to user error/lack of training. It does take some getting used to compared to any other machines I've used. Good luck! :)