Plastic quality variations

My current collection is a mix of the generations line to include the war for Cybertron trilogy as well as the studio series 86 figures.
Is it just me or is a plastic on the studio series 86 figures and fear to that of the war for Cybertron trilogy figures? The latter appear to be "more solid" feeling even though they are both very hollow.
Is it just me or is a plastic on the studio series 86 figures and fear to that of the war for Cybertron trilogy figures? The latter appear to be "more solid" feeling even though they are both very hollow.