Twins also offer the reassurance of a second engine, especially when flying at night, in poor weather, or over water or mountains. Be advised, though, that most companies won't rent a multiengine airplane to you unless you also have an instrument rating. The multiengine rating is one of the quickest and most economical add-on ratings for pilots to pursue. No written exam is required. A quickie course is fine if all you want is the rating-but if you really want to become a safe and proficient multiengine pilot, you should take your time and follow a thorough training program.
Twins are complex machines.
They are very safe in the hands of a skilled and competent pilot but can be unforgiving with an inexperienced beginner at the controls. If one engine fails, for example, asymmetric thrust can cause the airplane to yaw severely. Much of the multiengine flight training curriculum centers on handling such emergency situations. Chances are, you can work on your multi at the same flight school where you earned your private. Ask your flight instructor.