Instance dev is working on an update, I saw him mentioning on twitter that Rudys work on an IG app has put some fire under his ***. I bet there will be an update pretty soon.
I agree that when the upload hangs in Instance it seems to be something wrong in the text and tags, some characters is messing when submitting and it just stands there "uploading". I had some " and ? In the caption, after a few days of trying I shortened the text and removed the ? and suddenly it uploaded. I believe I tried the same caption in Metrogram Instagraph and it also hang.
Following Rudy on twitter is blowing my mind, that dude is cracking the IG features one by one in crazy speed. He's a genius. Looking forward to his app.
That said I don't mind supporting the Instance and Instagraph devs, the more the merrier!