To get more responses, you might need to rephrase the question. I believe you are wondering whether it is preferable to have a .327 J-frame revolver with a six round cylinder or a 9mm J-frame with five rounds.
I can only speak for myself and I reason that a personal defense revolver should use commonly available ammo for better serviceability. While .32 caliber revolvers have been around for a long time, they are no longer as popular and there is not as much variety available as there is for. 38 Special.
However, in a self defense scenario, six rounds are better than five. You need to weigh the benefits of 6 rounds vs. 5 against the benefits of being able to more easily acquire ammo and to do so at much lower prices. Lower prices of .38 Special and 9mm enable you to do more practice shooting and to stock up more ammo. If you have close family or friends who use .38 or 9mm, it would behoove you to be able to exchange ammo with them in a crisis.
As for moon clips, I have never used them nor am I inclined to do so for a small frame revolver. I like Speed Strips or HKS Speed Loaders. Moon clips unnecessarily introduce an additional failure mode. These small framed revolvers are intended to be last ditch, back-against-the-wall, no-other-way-out personal protection. With this in mind, I keep my gun as simple as possible. That's just the way I see it.