It has the same startup and similar head invunerability to µ's 2c, though the overall hitbox isn't nearly as good. It's definitely a capable tool.
There are situations where it's going to be better than 6a, and situations where 6a is going to be better, you just have to use whatever the time calls for.
That's really more of a gameplay question, I was mainly looking to offer help with combo routes and optimization charts,