I'm a big fan of Christopher Lloyd, and I really love the original short story of this. But I'm not a really huge fan of this version (though I don't exactly hate it either).
Christopher is very good in this (and it is the sort of role that seems tailor-made for him). Alan Ruck makes a pretty good job with the small role of the thankless father. And Haley does show a lot of personality and charisma as the main kid, even if he is a bit too "soft and nice". (I swear I saw a version with Alex Linz in the role - who is a lot more inheritantly mischevous. Maybe I just imagined it).
What I don't like about this is that fact that a lot of the broad wit of the original story has been severely toned down and "cutsified". I half-suspect it's because of the mid-90s era, the time of PC and everyone in America is expected to to be gushingly sweet to each other, and nothing bad or mean should ever be shown of tv, or that sort of thing. The whole while feels really tame (and cheap), and really lacks the dynamic punch that made the original story so good.
It's alright as a cutsey family film for undiscerning kids, but it could have been a lot funnier and more "rascally".