I would point out, for those of you who want Lightroom on the go, that you can already have it. Not only that, you can have the full Lightroom. Just get a Windows 8 Pro tablet (not Windows 8 RT, you need the full Windows
. I currently use a Surface Pro, and I have both Lightroom and Photoshop installed on it. I can use it out in the field for countless hours so long as I don't forget to bring along my charging block and my AC converter for my car. The Surface Pro includes a stylus, which is actually a very intuitive way of working with these apps small controls on the high density screen...and I actually find it is a bit more productive stylusing my way through LR than mousing my way through it on the desktop. You have all the simultaneous multi-input capabilities as well, so you can switch between using stylus, touch, and kb/touchpad at will, so you can always use your most productive device to perform commands, move through the UI, etc.
Anyway...for those who don't want to drop $100 a year on an iPad app that is sure to be a shadow of the full LR, especially if you already own an LR license, just pick up a Windows 8 tablet. Dell now has one that has a screen resolution with a higher density than the iMac laptop retina displays, and it's competitively priced, for those who want a really nice device to do their photography work with. The Surface Pro 2 should also be a pretty nice device, with its improved battery life, as it also included the stylus.