I actually was in two of these pod classrooms (or what Aldine ISD called clusters) for first and second grades. Cluster A for first and Cluster C for second at Hidden Valley Elementary.
To be honest, I kind of liked them. I was briefly in a regular classroom for a week in second grade before moving back to a cluster, and I thought it was kind of boring in such a small, confined space.
I don't remember having any problems learning in a cluster classroom. So I'm not sure why people these days speak badly of them.