Instagram Instragram is leading the pack with a great balance of photo mods, sharing, and social commenting. It has the most users, and makes all pictures perfectly square. This makes the mobile browsing experience really good because all the pictures conform regardless of whether they were shot vertically or horizontally. Only bad thing is - Instagram doesn't save the original version of the picture, you have to stick with you modified final copy.

picplz Picplz has a really great set of photo mods (filters) and is a strong competitor to Instagram. Honestly - I like their filters more than Instagram's, but the navigation and browsing experience within the app is rough around the edges. For one example - it's hard to see who is following you so you can follow them back without having to go to the full-size website. Big pro - they save the original photo so you can keep that version, plus you can change filters later if you want to try a different one.

Burstn Burstn doesn't have the same traction as picplz and Instagram, but I think it is a beautiful, creative app. The app browsing experience is really good, and they have a lot of filters. Almost too many. Most of my friends aren't on it though which means I don't want to use it much... maybe it will become more popular over time.

Path Path has been the center of both a lot of praise and disappointment - it's focus on 50 friends or less is very unique. Instead of following people in Path, you "share" with people. That makes it very private and intimate - if that appeals to you, you will love Path. Their recent app update included comments, so now you can have great social aspects. However, you can't put filters on your images, and you can't share photos to Facebook and Twitter - it's truly an experience only for your closest friends. Unique feature - in addition to taking a pic, you can optionally share a short video.

Flickr Flickr is a staple photo sharing website, and its app is a very strong photo sharing option. Especially if you are a Flickr user already, it will integrate with the tags, sets, etc. that you already have. Lots of sharing options - but like Path, no photo mods/filters. I've never really been focused enough to always upload to Flickr... given that I had Facebook photos and such. So this option doesn't appeal to me as much, but I'd imagine many people would prefer this very robust app option.