JND's may "look real" as Gary says, and they do have lively expressions, but do they look like the actors?
I'd argue that Inart's Harry and Ron are stronger portraits, definitely so with Harry, and Inart's Ron looks happier to me with JND's looking a little... resigned? The Inart one looks like it has a bit more humour to it, while JND's looks suited to a pose where he's shrugging or something like that. Both expressions suit Ron's character, but the touch of melancholy in JND Ron's expression makes it a bit less attractive to me than the more cheery Inart one.
With Hermione it's closer, but without high quality pictures of Inart's updated version it's hard to tell. I do think that JND's Hermione has got just a little bit too much of a glint in her eye - too mischievous, which doesn't really suit the character that well at this point in the series. Inart's expression is more of a happy medium between a blank expression and the strong emotion of the JND portrait.
The fact that the JND figures look "more real" actually might work against them in a sense, because if they're not perfect likenesses they fall into the uncanny valley more easily.