I have tried and tested all of the following leather conditioners...here is a quick overview of my findings...
Lexol: Probably the best for conditioning the leather. Makes it much more supple, but it doesn't smell that good and it makes the seats very sticky. It doesn't contain any ingredients to make the leather look better, only to condition it. I use lexol on older cars with drier leather.
Pinnacle Zaino and 4*: All very similar. They all smell excellent, look great, are easy to use and cost a lot! The differences between them are suttle, but my favorite is 4* followed closely by Pinnacle then Zaino. To me, 4* lasts slightly longer, is more dry to the touch, and applys more evenly. Pinnacle probably has the strongest smell of the 3, but they all really do smell just about the same. But, considering how similar they are, I choose 4* because its slightly better in performance and is the cheapest per ounce.