Welcome to the forum Nikki,
I haven't tried Ultralite but have a few friends and family members who have - they had success at the beginning but found it difficult to stick to.
I'm currently on the Tony Ferguson diet plan (started on Monday) and the shakes are very yummy on this one. Have a look at the site http://www.tonyferguson.com.au
and see what you think about that plan. Don't know about the price difference between the 2 products, but I know this one works.
Best wishes for whatever plan you decide on.