I really like this activity, especially with verb conjugation, because it forces them to see the structure of the sentences and specifically the conjugations. It's a bit of work to start, but once you make a set, you can keep re-using them with that unit in future years. I also have my first group cut out each set to save myself some time.
The kids also enjoy it because it's very kinesthetic and helps them to process sentence structure. And of course, a little competition never hurts either.