This is my situation as well. It is not for me, but my wife uses an iPad with MK as her laptop. However, she also has an iMac, and if she needs to do any multi-tasking or significant content creation she goes to the iMac. It's a nice set-up, but it is kind of expensive and somewhat limiting. It is expensive because the iPad (with 256GB) with MK almost cost the same as an MBA on sale plus she needs another device (iMac) to handle the heavy lifting. It is limiting because she can only really do the multi-tasking and complex content creation at her desktop. Now, this has not really been an issue for her because she doesn't need to do anything very complicated whilst on the go. It is probably semantics, but I would not say she is using the iPad as a laptop replacement. I would say it is more of a substitute. She does not try to get the iPad to do things that a laptop does well. She simply saves those things for the desktop and uses the right device for the task. BTW - my wife never liked the ergonomics of laptops, but seems content with the iPad + MK.
I have no hate for the iPad. They are great. I have one that I pretty much only use on vacation. But, I think saying that an iPad is a laptop replacement can be kind of misleading to people and create false expectations. It would be like if I said a laptop is an iPad replacement because you can; take notes, annotate documents, use the trackpad to sign and draw. Well, yeah....but, I would never attempt to sketch anything complicated on my MBA. Different tools for different jobs.
