i have a 5510 and use a couple of 5410's i would say it is a good fuel system from the pump to the injectors.they need a electric lift pump when added that solves the problem.our tractors have from 3500 to 5000 hrs with few problems.i have seen some other 5000 series with over 15000 hrs on the original motor.they are 4 wheel drive i have been amazed by how much them little tractors will do.if you are going to move dirt they need more weight.i have the cast wheels plus weights.the power reverser ,wet clutch,is a useful addition.one thing i do not like is the dry pto clutch.but the 5510 one lasted 3000 hrs.to me these tractors are ideal for a haying operation.i like the 4 cylinder motor,it makes the tractor longer. jd parts support is the best.my jd ag dealer stocks a lot of parts plus can get most others by 7:00 in the morning no extra charge.i believe there is a difference between jd ag dealers and homeowner dealers.i have several different brands of tractors.if i had only one it would be a jd.