When I read the phrase I was reminded of--I am reminded of-- Romans 16:7
Romans 16:7: ἀσπάσασθε Ἀνδρόνικον καὶ Ἰουνιᾶν τοὺς συγγενεῖς μου καὶ συναιχμαλώτους μου, οἵτινές εἰσιν ἐπίσημοι ἐν τοῖς ἀποστόλοις, οἳ καὶ πρὸ ἐμοῦ γεγόνασιν ἐν Χριστῷ.
On the one hand, there is nothing inherently comparative about the phrase here. It just means "eminent among the apostles." But there is a hint of comparison. Standing out among the apostles, Andronicus and Junia are more prominent than some--not by any means the most eminent--but not just your average, everyday apostles. As always, context is everything. If your boss tells you, "you shine among your co-workers," it does not necessarily mean that you are better than the other workers, but that is among the implications. Same thing here in both Paul and Rico's phrases.
I would go so far as to say that ἐν plus the dative, if the context supports it, can be idiomatic for an implicit comparison. I'm pretty sure I have read more examples of this, but they would be hard to track down because ἐν is so common.