Here is my opinion after paying 12 USD for everything listed and unwrapping it. Hopefully, it would be useful for people considering.
Quantity-wise and "whether it is worth the money", it is a lot of stuff for 12 USD. I think a single music pack alone (such as Rebel Rapture and Inspirational packs) in the bundle would cost more than 12 dollars at usual store prices.
As for how much of it I would use, probably very little (<10%).
Would probably handpick a few tracks in the bundle. So far, I do like what I hear from the music packs
Graphics would highly depend what you want in your game, I find that most art don't fit my game.
The styles and genre of the art varies a lot, front 16bit tiny-sized RPG Monsters to 3D-Rendered-Lookish of High Fantasy Pack. I would recommend to take a very close examination of what is available if you are buying it for the graphic resources. I think those sci-fic developers would benefit a lot from the bundle (I can't be sure, I am not one myself ><) with a sci-fic pack and a few more sci-fic stuff from the "Humble Bundle New DLC Pack".
I don't dig very much into the games or the game development software but the 12 dollars is very much less than what I paid for RMXP and RMVXAce individually. A good chance to nab the engines if you have been eying them for sometime. Ace even come with Luna Engine. I will have you know I bought Ace and Luna individually

(but they are good, really good)
With my bundle purchase, I can also strike out Game Character Hub from my Steam wishlist. I have been putting off that purchase because I wasn't sure it would be worth it. And now I have it "cheap".
Overall would I recommend buying it?
Yes I would
