The most notable difference at the moment will be:

 - The **computational power** difference between a PC & a tablet - tablets give you the computation power of a PC that is 6-8 years older, so even if you get the workflow on par with the PC, the speed will definitely be a lot slower. If you are working with the RAW format, then just exporting them after processing will take a lot longer than on a PC - even the fastest hexa-core desktop CPU today equipped with an SSD takes 11 seconds in the [Photoshop CS4 retouch benchmark][1].

Quoting from an article on [Blackberry vs iPhone][2] (written in 2008, well before the iPad, but quite relevant to the PC vs tablet computation power discussion) regarding the rate of progress in computation power:

> ...in just nine years, the specs that then described Apple’s top-of-the-line desktop computer now describe their phone.

 - The **storage space** available - tablets top out at 64 GB, so you are going to be severely limited even if you just go the JPG route

 - **Connectivity options** to transfer images from the camera to the tablet - more of a lack of or non adherence to standards than anything else though

 - **Interface** - Point & click may be a better accurate paradigm when trying to edit photos precisely. However, you can get over some of the limitations using a keyboard dock and\or stylus combo.

At present, a [MacBook Air][3] or [Ultrabook][4] is the most portable replacement for a full size laptop, and even a desktop that doesn't involve as many trade-offs as a tablet.

**Update (post iPhoto for iOS):** Touch devices do open up new forms of image editing, particularly from the ease of use point of view (once you learn the interface). There is a precision vs simplicity trade-off, but this should be good enough for all but rigorous editing. Do check out [Andy Ihnatko's experience][5] where he has shared some of the killer features. There are also quite a few iPhoto clones coming out now.


  [1]: http://www.anandtech.com/show/5091/intel-core-i7-3960x-sandy-bridge-e-review-keeping-the-high-end-alive/5
  [2]: http://daringfireball.net/2008/05/blackberry_vs_iphone
  [3]: http://www.anandtech.com/show/4528/the-2011-macbook-air-11-13inch-review/17
  [4]: http://en.wikipedia.org/wiki/Ultrabook
  [5]: http://www.suntimes.com/technology/12383842-478/results-make-up-for-awkwardness-of-iphoto-for-ipad.html