I would take the southern route i.e anticlockwise. If the Darford crossing gets congested you reall have no alternative, whereas you can often doge say accident congestion on M25 south by reverting to non-motorway roads.
Given good traffic information and assuming you are coming from west Midlands, I might even consider M40 to Oxford, A34 to Newbury, M4 east then A 329M Bracknell / Lightwater and onto M25 via Lightwater and Chobham.
This would all depend on time of day and weekday or weekend and is clearly more complicated than M40 or M1 to M45, but you do have more choices of alternatives if your satnav shows up major congestion.