Always since Filevault 1.0 which only encrypted the Home Folders.
It seems to have no performance impact so is a no-brainer.
Never had an issue with it, but I do Time Machine backup to a 1TB USB drive every month or so just in case. It's much better do enable encryption when the Mac is new as it skips over empty disk space.
On a full Mac it can take several days but at least runs in the background and you can still sleep/restart.