There are some pre-prints making the rounds suggesting the bivalent boosters don't generate a significantly superior immune response to BA.5 than boosting with the original monovalent boosters.
A few reasons to not prematurely react to these pre-prints:
first and foremost these aren't peer-reviewed yet. They may change once peer-reviewed.
these are immunological studies, which don't necessarily translate perfectly to actual effectiveness.
the numbers are small, we've seen a lot of variance in similar immunological data ( which makes it hard to rely on these sorts of studies for head to head comparisons between vaccines in general compared to more robust data ). That more robust data will be available in a few weeks.
the window of observation was only a few weeks. You'd generally expect a strong early response to the original virus, but over the long-term a broadening of the immune response to the variants. So later data may show the full effect of the bivalent vaccine.
in the companies' immunological data the bivalent vaccines had more durable immune responses than the monovalent vaccines, so there may be a subtle trade-off here where these bivalent boosters generate more sustained protection than the original boosters.
in prior data we haven't seen imprinting (aka original antigenic sin), so the weight of the evidence would bias against it until more data.
In any case, even this data suggests it is worthwhile to get the Omicron-specific bivalent boosters.
You will strengthen your immune response either way here by getting boosted.