A few questions:
1. What is the point of raising any levels past the point of skills? If I remember correctly, Serah learns her final MED skill in the 30's... what's the point of going any higher? Wouldn't it be more beneficial to spend points in other roles? Does a higher level = higher heals? Or is that Magic based?
I've currently got her at 99 RAV, 50 MED, and 50 SAB. Decided to start dumping points into COM. Noel is similar but with COM, SEN, and SYN.
2. Everyone is talking about Pulsework Knight/Soldier as the greatest SEN monsters. They only reach level 20 though so what's the big deal? I switched over to the Goblin SEN and his HP has already surpassed the Knight. Maybe I'm missing something? I'm also interested in the Flan SEN.
3. Are the chocobo's worth it? I just got a yellow one. I'm having trouble capturing red and purple. Are they worth it?
1. You mean aside from basic leveling and stat-raising in general? Not much, except that you get different stat bonuses depending on which roles you use to level the big Crystarium nodes, so it's best to hold off on maxing out roles that you want to save for leveling the big nodes. Even if you've learned all the abilities in a role, you still get that role's stat bonuses when you level it on big nodes. Also, you get a trophy/achievement for maxing out all of Serah and Noel's roles (raising all roles to level 99).
But yeah, I would say it's best to learn all the abilities in the various roles before trying to raise them to level 99. That way you get abilities earlier, and you have more leeway in planning which roles you want to level on the big nodes.
2. People like them because they're Early Peakers and, thus, easy to raise and use throughout the main game. They become more limited in effectiveness in the post-game, but throughout the main story, you really can't go wrong with them since they're strong enough Sentinels to handle whatever the main game bosses throw at them (though the last bosses might give them a little trouble) and they're really cheap to max out.
3. Some are, some aren't. The Green Chocobo stands alongside Flanitor as the best Medic monster in the game, and the Purple Chocobo seems to be considered one of the better Synergist monsters in the game. The Blue Chocobo is also a fairly popular Ravager. The Silver and Gold Chocobos are the best ones for racing (easy wins, especially with the Silver), and the Silver also happens to be one of the best Sentinels in the game. I don't hear a lot about people using the Red, Black, White, Gold, or standard yellow Chocobos in battle (though it stands to reason that the Gold is a pretty good Commando).
All that said, building a paradigm pack with three Chocobos is not a bad idea, because there's a passive ability that grants stat bonuses to monsters of the same type in a paradigm pack. With three Chocobos, all of their stats get boosted 30%, making for a very powerful team when raised correctly.
Definitely seek out other opinions though, I'm far from knowing everything there is to know about this game... this is just what I've learned as I read other opinions as to how best to go for the Platinum.