The free version seems to have 132 words in it; the premium has on the order of a couple thousand, if I understood the descriptive material correctly.
In the flashcard portion of the app, the English speaker is a male native speaker with a relatively neutral American accent (there may well be a way to customize it, I don't know). However, the Dutch speaker sounds synthetic, with a frequency range that suggests adult male -- but it sounds synthetic, like a program not a recording of a person. For some of the words, the results are compelling (mistig, veertig). For some of the words, the results are less good (oranje) and for at least one, I think it's actually wrong (scharlaken). The result on groen actually sounds like the person whose speech was sliced and diced for the rest of it actually _said_ that word for real.
Scharlaken is particularly weird, because the sch sounds right in verscheidene, but it is pronounced "sh" here. I repeated it a ton of times and I doubled checked the sound clip on nl.wiktionary.org -- it is supposed to be the usual sch and it just isn't.
So you cannot trust the pronunciation here: it sounds synthetic AND it is sometimes wrong in an important way. Can you use it just to learn the words visually/spelling? I did not detect any spelling errors, however, whoever put this together screwed up badly in the word mapping. You could argue about whether you should translate lightning as bliksem (which seems pretty straightforward) vs. bliksemflits (their choice). Ditto the way they translate donder. Whatever. But they translated pacifier (this is in a list of 132 words with _nothing_ about keeping the peace and a few other baby related words like diaper) as vredestichter, rather than fopspeen.
Synthetic Dutch speaker, pronunciation error(s), wildly incorrect translations = I'm going to delete the free app. Just fixing the individual errors in pronunciation and translation quality is not going to be enough to convince me to retry this product, because I'm _learning_ this language. I should not be able to detect these kinds of problems in the basic version of the product.