I "want to do a project with it" and "want it to succeed" more than I "like it as a framework because I've done production projects with it"

Why? Since it's in the official typesafe stack (a company founded by Scala's creator to promote it and it's ecosystem commercially), based on concepts taken from RoR, has rapid deployment without the need to pay JRebel 100$ per developer, and is supporting both Scala and Java.

So I see it as "finally something good happening to those who wait". It's the only way enterprises can start doing modern web development without giving up on their existing investment in the Java / Spring / Hibernate stack. My view on it? I can't wait to get a work related project done with it.

Lift is also an interesting option (Scala only though), but you asked about Play. Lift has it's learning curve, but it's creator claims it is better than Play in almost any aspect, and many tend to agree, but I don't know enough to judge...