The late-40s to the early/mid-50s Casper the Friendly Ghost cartoons had a higher budget and overall the overall quality was much better. Onwards, the quality did diminish quite significantly though the overall cartoons varied, some decent, many mediocre.
Famous Studios' cartoons are not for all tastes, but my opinion is that their early stuff and some of the early 50s output are good. While they were very formulaic they were always well animated and voiced with some funny parts, some poignancy and decent characters and their regular composer Winston Sharples could always be relied on to write a great and often outstanding score.
Admittedly though, by the mid-50s through to the late-60s Famous Studios' cartoons did get repetitive. While Sharples' music still shone and the voice actors did their best the animation suffered due to lower budgets and tighter deadlines, the humour became more tired and slow in timing than sharp and funny, the stories became increasingly predictable and rehashed and some characters started losing their initial spark, this is particularly true of most of the later Herman and Katnip cartoons.
'Not Ghoulty' is one of Casper's best later cartoons, one of the best since 'Boo Moon' by a wide margin and almost one of his best overall. Like the also surprisingly good 'Boo Bop' (the one with the ghost of Franz Schubert), it is nowhere near as repetitive as most 50s Casper cartoons, is one of the funnier, more spooky, best paced and cleverer ones.
Really the only big flaw is the animation. Some nice vibrant colours here and there, but sparse rather than meticulous backgrounds and character designs that look like they were drawn in haste betray tight deadlines and a low budget.
Don't tend to care for when Casper tries to teach characters a lesson, like he did in previous cartoons with the Ghostly Trio and Cousin Spooky. 'Not Ghoulty' is one of the better examples though, because he doesn't come over as mean-spirited or that he's taking things too far, one actually understands properly why considering the concept and it does induce some nice humour and atmosphere.
Winston Sharples' music score is outstanding as always. It is typically merry and whimsical, it's beautifully orchestrated, energetic and adds so much to the mood, his music has always been one of the best assets of the Famous Studios cartoons and it's not an exception here. In fact how it's composed and how it meshes so well with everything going on in the animation, story and action contributes to it being the best thing about the cartoon.
There are humorous and tightly paced moments in 'Not Ghoulty' and a nicely spooky atmosphere, and, while the dialogue is not particularly memorable, for a Casper cartoon the story stands out from the rest of them concept-wise and it is significantly less repetitive than most of the mid-late-50s Casper cartoons. Again like with 'Boo Bop', 'Not Ghoulty' is one of few later Casper cartoons to not feel too twee or sentimental.
In summary, surprisingly good for a late Casper cartoon and for a late Famous Studio cartoon in general. 8/10 Bethany Cox