What is a complete voyager collection?

[PANAMATIK]

Of course it is never complete! But I received my HP-10C for 39 $ today and now I have all of the original voyager models 10C, 11C, 12C, 15C 16C in working condition. I also bought the DM15L and a new 12C version last year.

What are the pros and cons for having the 12C platinum and the 15C limited edition? Are there more noticeable models around. And why is there the gap between 12 and 15 ?

Bernhard