SKY3DS (the sky3ds come with a blue button) has no game limit , and also confirmed to work directly for 3DS 9.4.0-21.
Sky3ds official news quoted here:
* It’s confirmed! SKY3DS can support the newest update – V9.4.0-21U/E/J. (12/12/2014)
* The new batch of SKY3DS card (no game limit) is releasing today! (12/10/2014)
The new SKY3DS card, which come with a blue button, has the exactly same features with the old one
except – no game limit any more.(Video)