Wouldn't say this is better then the first one but it still is an amazing game
First off you can eat enemies and turn them into egg's which you from then on can throw at your enemies, I wouldn't say this is the best thing about the game but it can be fun throwing eggs at your enemies, overall though it's a pretty good game the controls are not as good as the first one, but they still are not bad, it seems like when you are trying to get Yoshi's to float for a small period of time he doesn't always follow the controls and will float in mid stride of them when you told him to do it earlier which can lead you to some cheap deaths some of the time, other then that the controls aren't to bad, as I was saying in the beginning of this review playing as Yoshi as opposed to Mario, is fun but I feel like the pace isn't as good. In the first one you can fly through the levels, Mario is very fast and the controls are so good that you can go through levels without much stopping.
In Yoshi's Island, Yoshi does not move as fast and there are more strategic types of levels, this isn't bad I just prefer the 1st super Mario level designs, and how the pace works into the levels on the first one. Like I said this isn't bad, but if you really like the first Mario game a lot this may be a little distracting to you. The bosses were perfect, a lot better then the first one each one was totally different from the other and they were very enjoyable to play,(Spoiler Alert) and I don't think anyone can deny when they first fought against Bowser and he ended up changing into a giant, the music made the moment and it was one of the best scenes on the Snes let alone that it still stands out today of being a really cool yet somewhat scary setting that is very believable. The music is good but I wouldn't say as good as the first one, however the ending music is absolutely outstanding and makes a decent ending into an amazing one.
Overall If you liked the first one you will like this one, the level design can be quite good and there are also a lot of levels to keep you busy with this game, also if you like collecting things this is also your game, I found this sort of tedious but others might not I don't know, If you are a Mario Fan this is a game worth getting.