People say caviar is best because for them, their priority is durability, and they are probably afraid of lambskin.
Lambskin is far more beautiful and luxurious to me. I have both leathers, and my SLGs (credit card holder and mini o-case) are both in lambskin. This means these little guys get beat to death from use and being in my wallet. For sure, caviar stays looking pristine longer, but there is no comparison to the beauty of lambskin, even if it's a bit beat up. I would get lambskin as my first choice.
If you love lambskin and a top handle bag, the Trendy CC is the bag!
This season, Chanel introduced the mini Trendy CC. The colors might be a bit loud if this will be your only bag, and the colors scream of summer so the colors are not quite year-round colors. Also, some Trendy CCs have a rainbow C H A N E L which you may or may not like. Just FYI but these mini Trendy CCs are arriving now in the stores.
Good luck to you!