You might say it's the best+.
http://www.nintendoworldreport.com/news/42076/rhythm-heaven-megamix-announced
The long awaited Rhythm Heaven compilation for 3DS will launch this year in North America.
Known as Rhythm Heaven Megamix, the game is confirmed for a 2016 release. The 100 missions will include 70 levels from the GBA, DS and Wii Rhythm Heaven titles and 30 original levels.
Hm, if this is mostly content from previous games, I'm not sure I'm interested. Maybe if the game reaches $5 like the previous ones did...The game has new content pretty much equivalent to that of a new entry in the series, all the other songs are icing on the cake.