I just bought a Burton 2012 Hero 155cm board and i have Rome Libertine boots (44,5 cm).
Now i'm looking for Bindings that are matching with the EST system.
I'm looking at the Burton Mission & Burton Custom.
All Burton bindings should be similar in "strength" baseplates are guaranteed for life, I've heard of issues with the highback on the Diodes but you're not looking at those, and I'd also expect the ratchets and ladders to be better on the more expensive bindings.
That said: The missions have a feel rating of 6, the customs have a feel rating of 4, the board you bought has a feel rating of 3 I'm pretty sure, so the customs would probably be a much better match.
Hope this helps!