I have had two libra pros before getting my current Kindle three. I know you seem to be pretty happy with the Libra Pros but I was not. I have found that the libra pros were very fragile when compared to my current kindle. If I put the libra pro down too hard or breathed a little to heavy the libra pro would be done for good. The last of the to libra pros was set asside for aproximatly on month and never turned on again. Nevertheless I do not recommend the libra pros.
As far as the tablets go that you are talking about Iwould not bother buying any unless there is something additional that a tablet would do for you that your libra pro would not do. For example running one of the millions of apps availabel for android. Have you looked through a listing of all of the android apps and asekd yourself one critical question - how much are you willing to pay for the ability to run these apps.