From what I have heard, not much.
But, speaking from experience... I mated an Adcom 555 for the woofer, with an Adcom 535 for the mid/tweets
on a three way L100S Duanage modded for me to be bi-amp-able.
The Adcom 535 is different sounding from the 555. I won't elaborate as it is often too subjective. But this is one reason why one might fore-go the active part (which has it's detractors), from a straight up passive bi-amp.
A tube amp for the mids/tweets with a solid state for the woofer is another example, if the gains can be matched.
I can't speak to the active bi-amp as I haven't gone that way yet, but gains can be had using two different amps.
I won't say it's as good as an active because I really don't know, but... it can be more cost efficient
IF, you have a guy like Duanage around.