Can you describe the process you needed to go through to make a universal version with pretty radically different UIs on the two devices? Is your code littered with if (deviceName == @"iPad") { ... } else if (deviceName == @"iPhone") { ... } type statements? How do you seamlessly switch off from let's say a drill-down navigation view stack to using a list/detail split view? Anyway, congrats on getting your app converted, sounds cool.
I wouldn't say it's littered, but yes, I have a bunch of statements of that sort.
The "split view" thing is new for the iPad, and as a lot of apps use lists to get you to a detail view, we will see it a lot. The split view takes two views and places them side by side when the iPad is held in landscape mode. I was able to stick two of the views I already have for the iPhone app in there. The left side typically holds the lists you drill down into, and the right side holds the lower detail view. Think like on your computer when you look at iTunes, you have a list of playlists on the left, and a bigger detail view like a grid of album covers on the right. In an iPad app the right side might be a map, picture, or game board maybe, and say a drawing app could have the image on the right, with a bunch of brush settings on the left.
The split view automatically changes when you move to portrait mode, making the right side view full screen, while the left side view disappears, but there is a button to make it pop over on top of the screen to make a quick selection. In a drawing app the image could go full screen, and a button makes the brush settings popover the image. When you touch a brush shape or color swatch it might disappear again.
The split view manipulates those list and detail views. So I was able to tell the split view to use the top level list on the left side, and the detail map view on the right side. Having them appear and move and stuff as the orientation changes was not hard.
The views are mostly the same. The lists and map behaves the same. The interfaces I make in Interface Builder are different. Each device loads a slightly different version - I moved the toolbar and icons around a bit, adjusted some things for the bigger sizes and so on. The conditional stuff is throughout, but small things. I tell it to load this interface file for iPhone, that one for iPad. And when a person touches a track in the list to see the map, on the iPhone the map view slides in over the list, but on the iPad the map is already visible so I just tell the map to display the new data and skip the "push a new view on top of the old" thing I di for the phone. It's mostly little stuff like that. Not bad, really.
