If you're an avid watcher of all things Adin (haha) you'll know that I am on a mission to research all things mobile in an effort to maximise our time efforts in business. The mobile phone and specifically iPhone has grown up quite considerably and we are now able to do some high end work on these small supercomputers.
Mobile movie making
Overall limitations: As far as I know there are no multitrack mobile movie solutions - in other words you can't layer multiple video tracks on top of each other and jump between video angles. It's either a one take affair or jumping between various clips you've taken.
Overall power of iMovie:
As always, Apple's offering is simple, yet powerful. You have various but limited text options, but in various title, intro, outro, and lower section formats - which is nice.
Editing: The editing features in iMove are the best available right now. You split your videos at the playhead, leaving each respective clip of the video in place and in time.
Limitations: The background music and font selection is very limited in iMovie.
Overall power of Splice:
Splice offers a clip by clip approach with loads of fonts and background tunes. It also has a "blur" feature which is great for blurring out intros and outros.
Editing & limitations: I found the editing in Splice is the only real downfall in comparison to iMovie. So if splicing and chopping is very important to you it might not be the app for you. In order to "chop" a clip you need to duplicate the clip and then trim each clip into place - a laborious affair.
Conclusion: Apple always win the polished overall package prize, but in terms of the features you really want, I'm a Splice fan (Although, ironically, it doesn't do a very good job of "splicing" at all!). The fonts and music included is really a big thing when you're editing on the fly in order to post something online.
Edited with iMovie:
Edited with Splice: