I have the iLivewell and it stinks. You have got to be quick on draw to take a pic. The app has a variety of species (all bass species, catfish, all panfish, musky, pike, 3 or 4 trout species) to choose from. Weights are calculated by length and girth, so you have to get the measurements before you can get a weight that won't be completely accurate. By the time you get all the measurements and snap the picture the fish has been out of the water for way too long. I believe in getting a fish back in the water ASAP, so I just take a pic, weigh it if its a donkey, and release them. This app is a waste of money and Bassmaster mag was where I found the reference to it.
The only app I use is Navionics, but I only use it to mark tracks and waypoints. I don't have any experience with any other apps, so that's the best I can give you -- DON'T GET iLIVEWELL.