The most important queston: Is it your only toilet?
Secondly, are there any problems with the curent toilet's mounting (rocking, moving,etc.) What's the sub floor material? Finish floor? Does it sit directly on the finished floor? Are you changing the floor?
If not, covering the footprint of th old toilet could be a major issue, especially if your current floor was installed around it. If it's tile that runs underneath, that probably would clean up OK if the new foorprint doesn't cover the old.
The input and output connections are pretty much the same, though made with different materials today.