Well if you have any of the synths you can just open them up and have full control over everything and then save the result as a new preset in Analog Lab which is pretty good. I think for many presets the editable controls are pretty good for tweaking though without opening the full synths, and at least there is a healthy number of them.
I think about Analog Lab as more as a Rompler in terms of musical usage, something like one of the E-MU racks, which I like about it, but additionally it also uses a fantastic sounding synth engine to create the sounds.