I have the Elemis one and have already opened it. I bought it because I use several of the products in it, plus I've been using the travel sized versions a lot while travelling recently. The calendar just happened to have exactly the kind of things I'd buy anyway, so was value for money for me. I do often buy the QVC offers too so I agree it's worth shopping around if you like Elemis.
I already opened it because I need an empty one to make an advent calendar for DD, and I bought it for practical reasons rather than the surprise/fun element. I've bought LF to open in December. Having opened it, if it was my main advent calendar I'd have been disappointed. It's not the products themselves, it's that the drawers were mostly large with very small products in, and no tissue paper or packaging. So the actual experience of opening it was quite deflating, and it felt like lots of tiny tubes rattling round in big empty drawers. I'm still glad I got it, but glad I didn't save it for December!
I do love Elemis - I'm 44 but post-chemo with very dry & sensitive skin, and Elemis are the only products that do t irritate my skin. Hence why I need travel sized products, I won't use anything else!