You elude to the problem with such a question in your post * I want to hear real opinions from experts and know the pros and cons and recommendations.*
Questions that are solely based on opinions just simply do not fit this site. This has greatly to do with the type of website this site is.
In a broader sense the internet fills two basic roles. It educates and it entertains. This site has almost solely to do with educating people through questions and answers to a plethora of topics.
When you ask a question that garners opinion that is not based on facts then it really takes away the chance of educating people in any meaningful manner.
In your example you may get 10 answer saying completely different things that is solely based on harmonica players opinions. The question you have to ask yourself then is how does these ten different answers educate you in any meaningful manner?
Those ten answers may all be equally valid opinions. How would we decide on the quality of these opinions? and what purpose would such answers fill? The answer is not anything meaningful.
This site is a great education tool. So when posts on this site do not educate people not only is it off topic but it also threatens the viability of this website. This has a lot to do with why the community's guidelines are enforced at times harshly.