The entire OGInstagram interface is identical to Instagram's in every way except instead of reading 'Instagram' along the top part of the interface it says 'OGInstagram'. Everything else – profiles, photo feed, search tools, etc. – is exactly the same.
The main (and pretty much only) novelty on OGInstagram compared to the official app is that when you press the share button you'll get an option not just to share the image or video link, but also to download it. This download takes place in the background and it goes directly to your downloads folder.
OGInstagram is an Instagram client that offers more features than the official client. The best part: it makes downloading videos and pictures from Instagram easy.