Liko81 wrote: You CAN, however, reach a shoulder holster relatively easily, IF you have the use of your right arm.
Or left.....or Strong or Weak side.
A person can easily draw from most shoulder holsters with either the strong hand or the weak hand, it is just one more thing I like about them. This generally applies to cross-draw holsters worn about the waist (in front) also.
Occasionally, I'll carry my Ruger SP-101 instead of my P-13, but I am so used to shooting either... that the differences in operating them should not cause me a problem.
The original poster makes a good point however, if you are one of those "gun of the week" type persons who has a different weapon on every time I see you, consider this question: In times of great stress...will you be able to effectively bring your weapon into play? There may not be time to fumble even the smallest amount.
Just make certain you are intimately familiar with any weapon you choose to carry for self defense...and try to keep your weapon choices and your practice with them as homogeneous as possible.
Just my .02 on it.