I have own 5" eReader JINKE, it is fit for traveling with 3 weeks battery per charge. 6" SONY PRS505, 6" JINKE, 6" ONYX (Stylus+wireless). 8" IREX iLiad2 (Stylus+wireless), 10" DR1000S (Stylus) and several 6" LCD screen (stylus)

Any of them has it own benefits, even myself,not only use for research but also for different purpose. Just swap SDCARD.