Neither is “better”. The right one depends on what matters most to you.
An estate agent can potentially achieve a higher price but takes time: valuations, viewings, offers, chains and the risk of a buyer pulling out. A direct buyer is usually quicker and more certain, but the offer will normally be lower than an open-market sale. Ask each option for the likely price, timescale, costs and who the buyer is. If speed and certainty matter most, a direct sale can make sense. If you have time and a straightforward property, an agent may be worth trying first.