Passive.
Active = just one more thing to go wrong. Ignoring extra tone control, which is, IMHO, superfluous with modern amps, the only other reason for active (and one of the reasons Alembic bothered to put so much effort into it) was to drive a long cable and reduce tonal loss that way. These days, cables are vastly improved, but I use a radio anyway (because I'm a clumsy oaf who treads on and breaks any cable, no matter how bomb-proof...). There's literally no place for active in my setup. It could be argued that the radio link is active, but it is supposed to be a clean link with no EQ, and that's how I run it. The bass version of the Samson Airline actually does have a pre-shape function if you want it, but it doesn't sound good, so I never use it. This also means you can save a few quid and simply buy the guitar version - they are otherwise identical.
Sorry, rambled a bit there!