There are many NES games which are good, but require some tolerance and patience from a modern gamer to appreciate. SMB3 is not one of them - it feels like a refined modern experience, without archaic bullshit. The challenge is there, but it feels rather fair and steady, not caused by unreasonable design choices.
The soundtrack and visuals are great even before considering the hardware limitations. I used to prefer the All-Stars remake, but after playing through the original I appreciated its distinct vibe more, rather than Super Mario World feel that I always can get just by playing the actual Super Mario World. The only thing it would really benefit from - saves via battery or passwords, so you don't need to keep your console overnight if you can't beat it in one sitting.
The soundtrack and visuals are great even before considering the hardware limitations. I used to prefer the All-Stars remake, but after playing through the original I appreciated its distinct vibe more, rather than Super Mario World feel that I always can get just by playing the actual Super Mario World. The only thing it would really benefit from - saves via battery or passwords, so you don't need to keep your console overnight if you can't beat it in one sitting.