Actually inside mk1 pickups are Split coils (read: P bass pickup), their tone are very similar to classic Precision bass pickup. But MK1 preamp on Ibanezes do a lot of EQ while flat: it adds lot of sizzle.
Lows are not thunderous, these lows lost in mix (blame mk1 pre).
IMO, mk1 pickups are good pickups.
MK1 pre is a good preamp... NOT!
PS: the best thing in ibanez basses are playbility and comfort, you can always change electronics.