Notar Fan thinks there are less parts in a Notar (gramatically, it is "fewer parts" but let's not go there...) Notar Fan's name give a bit of the story away, I think.
The advantage of a Notar is that its parts are not exposed, they are tucked inside the tail cone, but they are there. This means that the Notar is robust to damage from hitting trees or the ground, much more so than a tail rotor. It is also much quieter, because it makes all its noise inside the tail, which muffles it quite well. But, by strict count, there are many more flight critical parts in a Notar than in a conventional tail rotor, but out of sight, out of mind.
1) A Notar has a full tail rotor inside its shroud, this is the "fan" that makes the air. The fan is a variable pitch device with multiple blades, very similar to a fenestron (the first gen Notar used a Eurocopter fenestron inside the tail).
2) It has a variable area nozzle, controlled by the pedals, usually a rather crude can that rototes and exposes less or more area to power the tip jet (the jet is the real anti-torque device in a Notar, and the great power absorber).
3) It has a Coanda slot that provides some share of anti-torque during hover in very calm conditions, when the rotor wash falls on the tailcone (typically less than 10 knots of forward speed, and less than 5 knots of rearward) . Otherwise the Coanda slot is a power absorber, since it dumps the fan air.
4) It has a rudder usually on one of the vertical fins, that is controlled by the pilot's pedals, as well.
5) On some models, it has a rudder controlled by an automatic SAS system as mandatory equipment (due to poor stability).
Notar flies back to base after some failures because it has such extensive rudder and fin area (the flyback is aided by the rudder, which is a yaw control, of course, at forward speed). The rudder is needed because the tip jet is such a poor anti-torque device that it does not contribute to yaw stability at all. Any helicopter could be provided with the extra fin and rudder area, which adds drag (reduced range, more fuel needed) and weight. With such a rudder, the fly home would be easier for any helicopter, but neither design rules nor market desires ask for such capabilities, so they are not provided. Nobody thinks too hard about a rudder failure in a Notar, because that is not a failure they practice! Combat damage to the tailcone exposes the aircraft to the horrendous possibility of a new, custom tip jet somewhere, creating a new, custom control where it might yaw or flip the aircraft in strange ways.
As posted here many times in the past, the theory of an efficient light weight, failure proof, quiet anti-torque device was hawked by the Notar salesmen many years ago, it was described on the Discovery Channel in hours of hype. The proof is somewhat less wonderful, as shown by years of experience. Notar robs performance (lost payload or higher engine temp), it is a sloppier control system, it needs more parts and complexity, and it costs more. It is somewhat safer and somewhat quieter, so the marketplace can make its mind up if it is "better".
Those who want a Notar buy a Notar, others don't. The relative sales of tail rotor equipped helos to Notar equipped helos tells the story, I think.