Some examples from dictionary.com:
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JUICY
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adjective, juicier, juiciest.
1. full of juice; succulent:
a juicy pear.
2. very profitable, appealing, interesting, satisfying, or substantive:
a juicy contract; a juicy part in a movie.
3. very interesting or colorful, especially when slightly scandalous or improper:
a juicy bit of gossip.
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SUCCULENT
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adjective
1. full of juice; juicy.
2. rich in desirable qualities.
3. affording mental nourishment.
4. (of a plant) having fleshy and juicy tissues.
noun
5. a succulent plant, as a sedum or cactus.
In other words, the first meaning of the two words is the same. The second is also relatively similar. But then the differences grow slightly bigger. And as mentioned above, "succulent" can also be a noun.
In daily conversation and in the first meaning, probably, "juicy" would be more natural.