Td5 auto I tow a 1600kg caravan, family of 5 and dog and fully loaded never misses a beat, you do have to read the road ahead and anticipate hills. As for reliability have recently change auto box oil for which there is an argument that you never need to do it, thread on here im sure. Its a right bitch to do and you just cant check the oil, undo bolt if it pours out you have enough, put bolt back quick.
Good luck