I had BN1 and loved it, in addition to the gearbox most had a different rear axle than the later cars that was lighter as well. The throws are long, the synchros are slow, and it is leaky, but it seems to fit the vintage sporty touring nature of the car, the engine has gobs of torque and you don't gain much by revving it.
I would never have guessed that it was a mechanical clutch, mine was very smooth on take up, and I never had any problems with it.
As far as the difference between a BN1 and BN2 I guess I am arguing for the BN1, but on the other hand you can't exactly go to the dealer and check off the option boxes you want. 100s for sale are pretty few and far between, and a reasonably priced driver will sell fast, so I would be patient, but ready to pounce when a good car comes along, regardless of gearbox.