I transitioned from buying in the LLC to buying personally to get better financing. Although your lender can say they would not exercise the due-on-sale clause, without something in writing, that's meaningless. The reason I am choosing to hold title personally (with a large umbrella insurance policy) and not transfer over is because, looking through the bank's eyes, if interest rates go up significantly, I would want to force all those paying super low interest rates into higher interest loans.
If you are paying 3%, but in 5 years the going rate is 7%, they could call the note due and you'd be stuck having to refi into a 7% loan (or if you chose to keep holding in the LLC, you'd need to do a commercial loan, which means higher rates and/or shorter terms).
I know "everybody does it," but I just feel better keeping it personally. I have 7 loans with the same lender. Transferring them to the LLC and getting them called would reek havoc for me.