The decision
A shared answering service can take and route calls through an agreed script. A dedicated remote receptionist can spend a scheduled shift on your practice's calls and other assigned queues. The right choice depends on whether the need is intermittent coverage or ongoing administrative capacity.
What to compare
If you want booking inside a specific EHR, eligibility checks and recall work, make those explicit requirements. If you mainly need after-hours messages and routing, test that call flow and its escalation rules. Do not assume that every service described as medical answering performs the same work.
Before you commit
A hybrid arrangement can also make sense: a dedicated person during clinic hours and a shared service outside them. Price the two responsibilities separately and decide who owns the handoff.