[quote name='cheddatom' post='1350154' date='Aug 24 2011, 12:34 PM']As far as I know, any LPF should be the same[/quote]
Heavens, no.
There are different filter slopes, resonant and non-resonant filters, different bandwidths of the resonant peak at the corner frequency... not to mention the differences in methods and circuits used by different manufacturers, even if they're aiming towards the same goal. It's like saying that every Jazz-type bass should be the same.
As an example, Spectrasonics' soft-synth Omnisphere has at least a dozen low-pass filters to choose from, and they all sound different.