Scarring, intensity of surgery & recovery

Generally speaking, phalloplasties are more taxing surgeries that have a more difficult recovery process than metoidioplasty. Some phalloplasties require multiple surgeries to construct the penis. You can learn more about recovery from a phalloplasty here.
A metoidioplasty leaves virtually no visible scarring. A groin flap phalloplasty leaves a very concealable scar on the groin, a thigh flap phalloplasty leaves a large scar that can be covered up by shorts, whereas a forearm flap phalloplasty leaves a large scar across the forearm.