Dumbbells are easier to program and easier to trust if you are newer to strength work. Kettlebells bring more flow and more single-tool versatility once you already know the basics.
In a small space, the real question is which one you can store and reach for without talking yourself out of the session.
Choose by the workout pattern
One tool is usually better at what you already do most.
- Pick dumbbells if presses, rows, carries, and split squats are the backbone of your sessions.
- Pick kettlebell-style work if you want more swings, cleans, and one-tool circuits.
- If the room is tight, adjustable hardware usually beats collecting multiple fixed weights.