How bad is it? It's disappointing to fans of the series, okay otherwise.
Should you see it? Only if you've seen the first 6 films.
This is a hard one to review, because it's only going to be seen by fans of producer (and writer) Charles Band's series and, as it is a departure from the series, will be seen as poor by them. For those who aren't fans of the series, it's... fair to middling. Instead of the gory horror of the other films, this one's more of a fantasy. It's directed by David DeCoteau, which will cause some to immediately claim it's bad sight unseen. Puppeteer Toulon meets a sorcerer who is being sought by three mummies because he has the secret to giving life to inanimate objects. Almost all of the puppets from the earlier films return, excepting a few that weren't popular. The film unspools exactly as you'd expect and the biggest flaw id the dialogue, particularly the lines of the mummies.