I just finished the first cup (Cobalt). The scoreboard says that there are at least 17 200 other people that has done it too.
This a super cheap racing game - approximately a third of the price of an AAA game like F-Zero/Wipout. It probably will not sell a lot more than 100 000 copies.
Nintendo is watching this and deciding the fate of future F-Zero games from the sales of FAST Racing NEO.