Pyron_Knight
Eater of Worlds
I'll answer my own question now.
1. My favorite Akatsuki are Sasori, Hidan and Kakuzu. Sasori had excellent character depth - better than pretty much every other Akatsuki IMO - and it's made even more memorable by his short time being in the story.
Hidan and Kakuzu werel...well, cool. They interacted well and brought a great sense of awesome to the story.
Even though those are my favorites, I still like each of the rest of the Akatsuki in some way or another. Deidara vs. Gaara = epic ifght.
With the Espada, I like Ulquiorra more than any Akatsuki member but the Espada team as a whole just isn't as good as the Akatsuki. While each Akatsuki has at least something I like about them, characters like Zommari and Yammy just hav eno value.
I think Ulquiorra, Stark and Nnoitra have some of the best depth in all of Bleach, though.
2. Espada, definitely. I like the Akatsuki cloak as much as the next guy but the Espada's varied designs and their releases make them far more interesting. With the Akatsuki each of them (with the exception of Zetsu) at least looks pretty much normal.
With the Espada, you got a guy with an eyepatch and shark teeth, a cowboy, Jarhead, boobs and the rest. Each of their looks really suits their personality as well.
And when you take into account their releases...yeah, the designs of the Espada are just way more interesting IMO.
Also, I gotta give Kubo credit for the Aspects of Death thing for the Espada. I thought that was a nice touch.