I like that it's simple, easy to use for my non-computer savvy patients as well as being able to send them images in their email so they can show family members who aren't with us during treatment! It has some features which are not intuitive or obvious at first glance but once you know how to work around those quirks this program does what we need very nicely. Nothing really! Just make sure your patient understands how to download pictures from the computer before starting any treatments (it takes about 20 minutes of training). We've been using enVision since our practice opened 11 years ago and have had no issues whatsoever until recently when one of the computers crashed and now won't boot up after an attempted reinstallation. The customer support was quick to get back to me and help out. They were also extremely helpful getting another machine set up quickly without losing data/files etc.,.