We created this website because we are calculator fanatics - much like you. And we see the beauty of the HP15c. In some cases we've been longing for the calculator for a long time. In any case, no one needs to give us a reason to get one.
However, it is difficult to "sell" the HP15c to non-fanatics. As example, to my children. Both are technically-minded: one has just finished sophomore year in engineering, and the other is in international baccalaureat and intending to get into engineering too. Both are users of the HP Prime, and swear by it. It gives them an edge compared with their peers that use Casios or Texas.
However, it is difficult for me to convince them to get a HP15c - when it becomes available within a year.
The first obstacle comes with RPN. No matter how I insist, they prefer the text entry method of the prime - with a clear view of the equation being introduced. They have never enabled the RPN mode in their Primes.
The second obstacle is the small screen. You need to know what you are doing at every time, You need to know what you have in the four stack levels. Also you have no alphanumerics, and you can't get any graphics. What is the point, also, to edit a matrix in such a cumbersome interface? Can't touch the HP Prime when editing matrices, programs, etc.
Calculating with the HP15c has become second nature for most of us - and that gives us incredible speed when using these machines - well above in many cases than when using the HP Prime or the HP50g - simply because we know the machine better and RPN helps us. But this speed does not apply to our children.
So, I have not been able to convince them yet. At this point, they cannot see any instance where they could not have a Prime with them. I can tell them that in my professional life I have seen people with their 48 on their tables - but for any of them I have seen 4 or 5 with HP17bII or HP12c (gold or platinum) and 40 people using 4-bangers. There is just some times when you cannot take a Prime with you - but there will always have a place in your jacket for a Voyager.
Me? I like the landscape format of the Voyagers, and I am now having a good time using the HP15c for really everything now. They will come onboard sooner or later.