Jigglypuff has hands down some of the best aerials in the game. Forward aerial and neutral aerial are good spacing tools. For up aerial, you can set up juggles. Back air is a godly kill move that usually kills around 110%. Down air, only to me doesn't seem as useful as Kirby's.
Compared to a lot of other characters like
,
,
.
. who have a lot of combos to use, Jigglypuff is a bit harder to learn. The characters I mentioned above, and many more, usually have a down throw to forward air. Jiggly doesn't have many combos, but if you're quite fine with that, you're good to go.
But keep in mind about Jiggly's weight. She can get KO'd around 80 to 90 percent, so be careful. Also, never only shield when going against a powerful attack. I once tried to approach a Lucina with Jigglypuff, I shielded, forgot about Jiggs' instant shield KO, and got destroyed in 0.1 seconds.
Jigglypuff is, I think, a quite fun character. Main her as you please.