Kindle Paperwhite 4 - For Russian.
Kindle Paperwhite has Russian Language support and dictionary, I believe. To read e-books from other retailers you'll need to covert them into the .mobi format, which Calibre can do.
Benefits between LingQ and Kindle are up to the individual user's preference. I think that up to reaching Advanced 2 here, LingQ has the advantage of faster word lookup, better support for expressions, progress tracking, and so on. After Advanced 2, and beyond, those benefits are still there, but their significance may diminish as you move on to more regular use of the language, including Kindle and paper reading.
Thank you. I went ahead and ordered the tablet yesterday. Looking very forward to trying it out. :)
Makes sense with the Advanced 2, Currently I'm at Advanced 1, but I find easier books/novels to be okay without looking words up too often.