Are adjustable kettlebells any good?

The signal is split. Garage Gym Reviews and BarBend praise the REP Adjustable as fast to change and traditionally shaped, but specialist community threads on r/kettlebell consistently note that adjustables — including the Bowflex 840 — feel awkward for get-ups and overhead work because the shape and balance don't match a true cast iron bell. Most reviewers recommend them for space-constrained home gyms, not serious practice.