BYKI is a flashcard study/quiz app. As near as I can tell, once you buy the (premium?) version, you get access to all the lists/card sets (I don't think they charge for the download more section, but maybe they do and I just don't realize because I haven't hit the free limit yet). You can decide whether you want to "study", use the cards in one direction or the other or go to the quiz, which is nice -- you can just go straight to the quiz without sitting through the "learning" portion. They use a native speaker. Some of their translations are a little iffy (Dank u wel is "Thank you"), but nothing like AccelaStudy.
If you want a flashcard/phrasebook study tool, BYKI is excellent. I've picked up a few words through it, but not enough to commit me to spending much time with it, because there are other ways for me to build vocab faster.
I think I got BYKI as a downloadable application for my laptop some years ago and had a roughly equivalent impression of it.
ETA: I'm going to retract some of the positive review because they screwed up the translation for sour cream (giving it as creme fraiche and no I'm not going to do the punctuation on that correctly sorry). That is incorrect (I mean duh), see here for detailed, correct explanation of the various kinds of cream ("room"):
I'm sensitive to this issue for two reasons. I'm allergic to milk products in general, and it can be very difficult to figure out how to cook in a new environment when translating the basic underlying foods is hard. I helped my cousin M. (from Mexico) figure this out (not for a Dutch word -- this was from Spanish) when we were hanging out with my Mennonite friends. It took a while, even tho M.'s English is fantastic, because we ultimately needed someone who had milked cows to figure out which kind of cream she remembered from her childhood.