It's just terrible.
The plot is stupidly predictable.
The voice acting is poor despite having great talent (Meaning the voices they put on sound awful).
The Guinea Pigs don't look anything like Guinea Pigs (Owned GP's for about 7 years now) and instead look like overgrown Hamsters.
The special effects are poor.
The music is terrible and repeats. Almot every track in this film plays at least twice, which is just laziness.
The scene where the kids treat them as toys and basically torture them is just stolen from Toy Story only instead of using toys they're using supposedly real creatures.
And the biggest problem, is that it's just not funny. I think I laughed maybe 5 times and not even proper belly laughing, just snickers really.
All in all, avoid like the plague unless you're an avid Disney fan and have liked everything they've ever done and just save your cash for something like Up.