Pro's have been covered.
Con's have been pretty well covered. Only one I would add is bulkier/less efficient fuel storage.
If you got a truck or bigger rig, not to big of a deal, small buggy or tight on space, little more hard to make things fit effectively. Pro of gasoline in this respect is you can make a fuel cell/tank to conform to odd shapes or fit into tight spots to get maximum fuel. Propane your stuck with pretty big tanks that only hold 8-10 gallons, plus if your using folk-lift tanks, you need to make them assessable to be able to remove them to change and fill.
O-ya, and your cooling system better be up to snuff, and purge it well. Air-bubble can = freezing reg. Freezing reg. = better have some hot water and time, cause you ain't going no where.