CD - The pros include tetra bricks which are a nice easy lunch on the run, I prefer the chocolate shakes and of course it is cheaper, but that is only if you are on SS as you have 3 meals whereas on LL you have 4. If you do SS+ and have 4 meals there isn't much difference as the actual packs are a bit cheaper on LL.
LL - there is counselling if you need the added support, their savoury meal packs are better than Cambridge, when on Cambridge I couldn't stomach any of the soups, whereas on LL there is Spaghetti Bolognaise, Chilli, Pasta or Shepherds Pie and they are surprisingly tasty.
On the whole both have their positive points. I personally am now on LL and pleasantly surprised, but I do swap some of the shakes with a friend who does CD as I prefer their chocolate shakes.