So I tried this today, and I must say I'm really hooked. From a user experience point-of-view this app is super smooth and lets you create cool slide shows in no time. At the same time, the degree of freedom given to you as a user is pretty high. You can edit the duration of each image by moving a slider and choose fading effects from a drop-down box. I wish more apps could be so straight forward and yet powerful.
Other things I liked (besides the fact that it is free) is the option to convert slide shows into video clips and the fact that I can send slide shows as email attachments straight out of the app.
For upcoming version it would be great to have an option to import images from online photo pages like Flickr, etc.
So far it's my personal favorite for slide show creating. Two thumbs up!
You can find this app on iTunes right here.