Two other off-the-shelf active crossover options are the Outlaw ICBM (out of production though a new one may be coming soon) and the Behringer DCX2496 (uses XLR in/outputs and may require adapters). The ICBM is analogue solid state. The DCX is all digital.
My last system incarnation was all active. In my experience, the lightened load on main speakers by subtracting the LFE component made no difference in audible quality. If anything, running the mains full range while "copying" LFE to the sub helped with room resonances and masked the sub location. (For the record, I listen to a lot of demanding low frequency music. Organ fiend.) This will likely be true so long as your speaker impedance remains normal at low frequency. Some don't.
Replacing the passive mid/tweet crossovers and bi-amping, on the other hand, was a significant improvement. But I think this was due to two factors, one being the stock passive crossovers weren't all that great; the other, more generally applicable issue (I believe) is heating in the crossovers can change their performance enough to be audible. There's also discussion of back-EMF and damping factor, but in my system and on my oscilloscope this problem didn't need fixing to begin with -- I think this problem is overblown.
In my system, long term, I'm retiring the active crossover, partly because my DCX proved to be unreliable, but mostly because I've decided I prefer the high-efficiency horn-loaded sound, and in those applications going active doesn't buy you as much. Lower amp power == much lower power dissipation in the crossover == negligible heating. Plus it's a lot simpler.
For you, if you go with passive crossovers to split out the LFE signal, it would be upstream of your amplifiers, so heating would be nil.
My system, my ears, my opinions. Hope it helps anyway.
