The decision in one sentence
Choose independent single-head capacity when your queue is varied and batches are small; choose synchronized multi-head capacity when repeated identical runs are large enough to keep the heads loaded.
The hidden variable: average same-design batch
A four-head machine can only exploit four heads when four matching pieces are ready for the same design. A shop doing eight-piece corporate orders may use all four heads well; a personalization shop doing many one- and two-piece jobs may not.
Why a fleet of singles is not “less industrial”
Independent machines can run unrelated designs simultaneously and preserve output when one machine is stopped. They cost more floor space and can increase operator walking and maintenance points, but they are operationally resilient.
When synchronized multi-head becomes compelling
Large uniform, team, contract and repeat-logo runs are where synchronized heads convert one setup into multiple finished pieces per cycle. The bigger and more repetitive the batches, the smaller the partial-head penalty.
What to compare after throughput
Service response, cap hardware, hoop ecosystem, sewing field, training, warranty, software, electrical requirements, floor footprint and the cost of having a large share of capacity down during service.