so is remote desktop. I work in an enterprise environment and use it all the time. Even from home though our VPN. It works better then anything thing else and costs us nothing. Nor does it break our IT policy, which states that all remote applications need to go though our 90 day stress test. Since this is almost never going to happen, we use what we can. I can say that remote desktop works wonderful for the needs we have. then there is remote assistance which also works wonders, both inside the environment and outside.
as to thirdparty stuff, I have used and tested a number and can say with a little certainty, all have their faults, including VNC.
as to the security concerns, you can block traffic at the router for this, so you can't go out or back in, or only enable it when needed.
This quote comes to mind...
"If knowledge can create problems, it is not through ignorance that we can solve them." - Isaac Asimov -