I just introduced Arcanis to my group with So Ye Shall Reap. I tweaked a couple of things to tailor it a bit more to a home game as opposed to convention play, but overall I found it a very well designed module. It has a great hook. There is enough intrigue in the short adventure to make it easy for players to think in character (and show off the system's versatile skill rules). The combats are all very different and do a good job of allowing the mechanics to be introduced in an easy to grasp way. And the nature of the adventure makes it very clear that it's a setting in which PC actions have definite consequences.
I haven't played all of the adventures that most others have, but having just been in your position I figured I'd share my experience.
We played for the first time yesterday, and two of my players told me today they've already ordered their own copies of the core book, so I'd say it went pretty well
