that's a pretty biased response there mikey.. it would be like me saying I prefer Coupes over hatchbacks.. I wonder why!
I drove BennyG's Echo and I liked it! It handled pretty well, maybe because he had low profile tires and bigger wheels, but still.. so would I!

and of course it was a 5spd so it wasn't as slow. I haven't driven the Yaris yet, I imagine it would be the same anyways, probably feels a little bigger though.
I also drove a Corolla S for about a month when my GF's car got stolen, it was automatic but it wasn't as bad as I thought it would be. I also liked it and I would probably buy either an S or an XRS as I would rather have a manual than auto, but if it was inminent to get an auto, I would probably settle for the Corolla over the Echo because of HP differences.
Echo RS - Yaris RS.. I'd hit it.. Corolla S or XRS I'd hit it too!