Hi Jayden,
I haven't tried Activa because the Yoplait light smoothies have less calories for more yogurt if I remember correctly. I've been curious about them though. Let me know if they're good, I'm getting a little tired of light yoplait strawberry all the time. (My store only carries 2 flavors, and I don't like the other one much.)
If it helps at all, just remember prunes are just dried plums, you got 4 peach and 4 plum!
Be brave and try them, they could be good. Plus, you already bought 'em.
The BL book suggests lowfat dairy products as part of your diet, and I know they make it easier for me to grab breakfast. There's a loit of good things about yogurt if you like it. I eat it often. (Be sure and post how they taste/how filling they seem please!)
Cheers, Jules