Anyway can someone tell me how good is the Monty's B41 vs B13 and B44 on the chrono and blackbird respectively? And does the number of jewels make the movement more sophisticated, complex, accurate or it really doesn't matter???.
To be honest there's not a lot in it in terms of reliability or accuracy. All are COSC certified, and all are pretty reliable. Breitling say that the B13 is the most tried and tested, but that's because it's based on the Valjoux 7750 which is one of the most widely used movements around. Number of jewels tends
to mean that a movement is more complex internally, but not
that it necessarily has more complications - it just means that there may be more parts moving next to one another that requires more jewels to reduce friction. Yes it's true that movements with lots of complications tend to require more jewels, but some relatively simple movements can have a reasonably high jewel count as well. For example the B13 with a 6, 9, 12 subdial config and date complication has 25 jewels, whereas the B41 movement in the Montbrillant (which is essentially the same in terms of function with a chronograph and date complication etc, but with a 3, 6, 9 subdial config) has 38 jewels (if my memory is right!). It doesn't mean that one is necessarily "better" than the other...... just different.
Historically, a higher jewel count was associated with higher quality watches, although too many jewels were also thought to make a watch less rugged as jewels can break more easily than metal components. But if ruggedness is not necessarily a consideration, more jewels may
lead to a longer watch life as there is likely to be less wear. However all this is dependant on movement design and it certainly does not necessarily follow that more jewels mean higher accuracy.
As I say, all Breitling movements are COSC certified so a 25 jewel B13 is as accurate as a 38 jewel B41.
Hope that helps a bit.