Whether people like it or not the Kindle is the most popular e-reading device around, with recent reports saying taking 70% share of the market. Furthermore, you can read Kindle books on many devices such as Kobo (upload your book and it is converted to EPUB) on Kobo Writing Life, Android, IPAD and IPhone with free apps from Amazon. Only Barnes & Noble and Sony is not supported as they use EPUB With the former you have to buy a ISBN number and have a USA bank account so for me living in the UK this is a no no.
Once, when a writer wrote books, first came along the typewriter and then the word processor. Today I believe it is Kindle Writer that will prevail as it is specifically designed to write books for the Kindle. It even works on Ubantu with WINE too. Since Mobiread was originally setup as a forum for mobi format for the Kindle it make sense to promote the Kindle here rather than any other device. That's my take anyway but as you say each has a choice.