[dotsamuelswan]

Addicting can be used as a participle adjective. You'd be hard-pressed to find a style guide that says otherwise.

[StavrosK]

Descriptivist pig!

[dotsamuelswan]

I couldn't possibly argue with that.

[StavrosK]

In seriousness, though, "addicting" sounds worse to me. "Addictive" is more standard, wider-spread and more sonorous.

[talmand]

As a non-expert English speaker with 41 years or so of experience, I feel that "addicting" is just fine in this context.

But that's just my opinion.