I pull conventional.
Conventional deadlifts place more emphasis on the back and spinal erectors. If you have a very strong lower back there is a good chance that you will be able to deadlift more using a conventional stance.
Sumo deadlifts shift some of the emphasis to glutes, hamstrings, quads, hips and upper traps. If you are experiencing lower back issues, or have a history of lower back problems, sumo deadlifts may be a better option.
Conventional deadlift - Lifters with a short torso and long arms will generally perform better using conventional deadlifts.
Sumo deadlift - Lifters with a long torso and short arms will generally perform better using sumo deadlifts.
Conventional deadlift - The bar must travel a longer distance.
Sumo deadlift - Bar travel is shorter.