It's very nice looking & functions great. Pretty barebones right now (can't even login to see your own photos), and sadly, it doesn't look like the Instagram folks let the developer have access to their upload API either (something that was hinted they might do). Supposedly, Instagram & Microsoft have been rumored to be working together on an official app that'll be released soon, so we'll see what happens with all of this.
On second look, this seems like a different "Metrogram" app than the one that made the news a few days back. That one was from developer Bil Simser (@bsimser). He was apparently the one who was requesting the uploading API.
The one listed here is from developer Nazer Aminou (@nas2lor), who also makes the popular app WP Shortcut Tiles. So I guess they both wanted to name their Instagram clients "Metrogram"??