Here's a bit of general info on preamps. One is not necessarily "better" than another, but they're just different-sounding.
Is one electric guitar better than another? Not necessarily: they just sound different.
These sonic differences will also depend on the type of microphone you plug into it, and the source material.
That said, the high-end Focusrite preamps have a very distinctive sound and they're quite good. But Focusrite has been making lower-priced gear the past few years (e.g. the Green Series), and those preamps in the combo units are not built much differently than other IC-based preamps.
I don't know any specifics about the Penta at all.
[This message has been edited by rick (edited 09-17-2001).]