To me, they are as safe as they can be right now. They are safe, but as I said, the only thing I'm concerned about is the verifiability issue. There has to be a plan in place by the House in order to verify the total tally, the details of the tally, and also the availability issue. As you mentioned, for many people who are in different ridings and who may not have good connectivity, a small-scale denial-of-service attack could actually easily prevent people from voting.
Both technologies do suffer from both items that I mentioned: verifiability and availability.