LL is more expensive but comes with small group therapy. I'm not sure why someone would go with Cambridge - except that there's someone else to weigh in front of and they do tetras which people find useful. Personally if I were looking to save money I'd look at a VLCD like Slim and Save which do everything online.
I haven't had Cambridge packs but of the others some are nice and some aren't. It's a case of finding the packs you like. Personally I did a combination of LL (for the counselling) and Slim and Save (for the nice meal packs!).
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.
When i did CD i found it easy to stop going to the consultant but with LL the other group members encourage you and check up on you so thrres much more support as well as the counsellor, but i love the CD tetra packs too
I've done both (now on Cambridge). I changed purely because of the cost & because I'd been there a while, I found a lot of the group sessions very repetitive & not very useful after a while. But did lose a lot of weight on LL.
Purely cost for me-as a single parent with 5 kids at home I can't justify the extra money on some counselling. I did try exante and slim and save but I need the actual physical going to see a real life person and getting weighed.