I haven't played with segment before, does anyone else have any experience with it? However, I am a huge believer in using one library/system to track events and use one system to ingest them.

One quick note, I've found that it's helpful to build a simple wrapper in my own system for the call to the external library - this means that I have just one place to go if I change who I use to send events to.

I do think this oversimplifies lead scoring a bit, that's an area for a whole blog post to or two - and this seems like a good starting point. This is just to say that being too quick to settle on a lead scoring method can cause a lot of incorrect assumptions later.