It wasn't my point of view really..s1mp13m4n had asked those who _used_ a JBL to comment and I finally remembered where I read that:
"The following book formats are supported: eReader DRM, FictionBook (.fb2), Plain Text (.txt), Mobipocket (.mobi), PRC, EPUB, RTF, PDF. For best performance, it is recommended that you use TXT (text) files"
quoted from the Ectaco Quck Start Guide:
http://www.ectaco.com/products/mater...e_QS_ENG1_.pdf