Are adjustable kettlebells worth it versus a set of individual bells?

It depends on space and movement type. Across the reviewers we read, adjustables like the BowFlex SelectTech 840 and Rep Fitness bell are praised for saving space and money on warmups and swings, but r/kettlebell users repeatedly note balance and feel are worse for cleans, snatches and get-ups. If you have room and do a lot of ballistic single-arm work, fixed cast-iron or competition bells generally win on feel; if space and budget are tight, adjustables are the consensus compromise.