Curse of Chucky is a surprisingly solid sequel. Most horror franchises run out of steam by the sixth installment by this is much better than Halloween 6 or A Nightmare on Elm Street 6, for example.
The fourth and fifth Chucky movies brought the series more towards horror-comedy, but this went back to the roots of the franchise and is a relatively serious horror film. It was also the first one to be direct-to-video and the first to be shot digitally.
Despite being less comedic, it doesn't take itself too seriously and manages to strike an appropriate tone.
Bride and Seed of Chucky introduced a family for the title character, but Curse goes back to having him as the only talking doll.
It was directed by Don Mancini, who created Chucky, has written all the films, and directed Seed of Chucky.
Brad Dourif returns as the voice of Chucky and even appears in the flesh for the first time in the series since the original Child's Play. It's pretty cool to see him, but it looks a little odd as they try to recreate his look from the time period.
Brad's daughter, Fiona Dourif plays the lead role. This may seem like nepotism that could hurt the quality of the film, but these movies don't require Oscar-level acting and she had already appeared on shows like Deadwood and Law and Order: SVU. She even had a small part in P.T. Anderson's The Master.
She actually does a pretty good job, considering she was relatively inexperienced at the time and the film largely centers around her character.
This was described early on in development as a reboot or a remake and it seems like it could be at first, but by the end, it's clear that it takes place in the same continuity as the previous installments and there are plenty of neat homages and references to the other Chucky movies.