"Semi-hard" sleeves i.e. Crumpler School Hymn

[rideDPU]

Does anyone have any experience with "semi-hard" sleeves such as the Crumpler School Hymn or Marware Sportfolio etc.? I am looking for a slim profile sleeve for my 15" T42 (no extended battery or anything). I have been reading a lot about the Tom Bihn Brain Bucket, but how thin is it? Any other ideas for sleeves that fit that category?

Thanks,
Mark