A bond suits most people with a defined contribution pension from a job they have left. You get control, a choice of funds and charges you can compare. It also suits people whose old scheme is winding up, and people who want every pension reviewed in one plan.
It needs more care with a defined benefit pension. That kind of scheme promises an income, and a transfer swaps the promise for a fund. We show you both in figures before anything moves, and sometimes the answer is to leave it where it is.