The pictures you displayed show just how insignificant lips are relative to overall attractiveness.
These are both attractive women that would rank as desirable (based on looks) on almost any scale in any culture. Yet, the fullness of their lips are different. So are their hair colors, and accents for that matter. Again, this is just one pixel of a much grander image.
As for what I think of full lips, it depends on the girl. I've seen a girl with a beautiful faces and thin lips get an "injection" done. She went from beautiful to a living poster child of bad photoshop and a perpetual duckface.
I think my lips are a plus, people (mainly guys) regularly remark on them so they must be more attractive. People don't comment on thin lips and people are regularly getting injections for bigger ones so I'm glad I don't have to worry about that. My brother has big lips too. Some people, such as Kate Middleton, are beautiful enough to pull it off. On other people, it can be really noticeable and detract from their face. I think big lips show femininity. I would be fairly disappointed if I had really really thin lips like the ones below. Lips get smaller as you get older too so my lips will not get too small hopefully.
I think it depends on the woman. Take myself for example - I don't have particularly full lips, but if I had those second picture big pouty lips, I would be the definition of a permanent trout pout.
Fuller lips can be sexy on the correct woman. I think celebrities who get their lips filled are silly, especially when they had other features that drew you into their face. Not every feature has to be perfect on your face. Take your second lady; her lips distract you from the fact her eyes slightly slant downwards.
Full lips are of course much better looking. It just makes your whole face look much better. I hate my thin lips too, it sucks. But it doesn't mean you can't look pretty with thin lips! Kate Middleton looks nice too.
Guys don't mind small lips (I think they prefer it) there are tons of tutorials on how to make them look bigger. Plus you can rock red lipstick. Really what can you do about big lips, it's a lot harder to take away than to add
There used to be a stereotype about black girls having big luscious lips, but i consider mine thin. I wear gloss sometimes but never lipstick. Maybe lipstick would make mine look bigger, but i dont plan to try it
Guys compliment my lips (they look really big irl) a lot and say I have DSLs (figure it out) and I like them but really I still don't get why it's such a big thing. I think lip shape and how your lips suit your fave are more important.