Ambiguous! Man has never existed as a vegetarian by choice. Humans have always eaten meat, vegetables, nuts, greens, and only until recently (2400bc).Being a vegatarian is a sociologic or philisophic choice. Some studies have shown the lifestyle to be healthier, but other disagree.Protein intake need be higher, since the composition of non-animal protein lacks more essential amino-acids. Add milk and eggs!
Less heart disease. It is difficult to study in a radomized double blind controlled way, but comparing cohorts of vegetarians to similar people suggests vegetarians have fewer deaths from heart disease though they do not live longer overall. It carries risk of vitamin deficiencies (b12) and low minerals (iron, calcium, zinc). From a societal and financial standpoint it offers possible benefits. Talk to your doctor.