Err...the plot idea, while not all that awful itself, was poorly executed, and I don't know why they felt like including that bit with the Muk at the end...okay, they needed to fill their 20 minutes I guess, but it really felt tacky and pointless.
However, for some strange reason, this is also the episode that made me laugh the most in a long time.
I just loved Dawn in this episode. I often felt like she's portrayed as the most cunning of the trio (while Brock = wise and Ash = creative as far as mental pro-traits are concerned), and her sharp remarks, and the way she talked in general, once again made her stand out as the "cool girl".
Whether it was her giving TR an internal slap in the face,
Jessie: The word 'impossible' doesn't exist in Team Rocket's dictionary!
Dawn: It's not like 'possible' does, either.
or just the amusing scene where she dances along with Brock while completely giving off this "God, why the hell am I doing this?"-vibe... I liked it lots.
Speaking of Brock, I found it funny how he'd completely lost himself in his oneesan-song to the point where he didn't even know why he was dancing anymore. I also liked big brother Brock in the scene where the group watches Meowth talk to the Psyduck:
Ash: What is he telling them?
Brock: Don't ask me.
Dawn: Will it work out?
Brock: Don't ask me.
Overall, as someone said, if the episode was to be judged in terms of plot, it was extremely poor, but personally I liked many of the minor tidbits here and there, so I wouldn't call it a waste of time.