102x768 isn't for everyone, but in text-mode it's all the same. I've no idea how many hours I've spent on a huge high-res monitor staring at a relatively tiny terminal window surrounded by a pretty desktop picture.
A 11" laptop, particularly the new MBAs, is less cumbersome than an iPad + keyboard and far, far more useful as a real development tool. Other than battery life I just don't see the point of doing this other than the "hipster" factor.
Just the ability to spin up a Rails instance on my own machine or run XCode alone keeps my iPad on the shelf when I'm working.
Sometimes people are surprised that the reason I buy macs is not because they're metal and shiny.
I didn't buy the 3G version, but I do use bluetooth for the keyboard all day and still get around 9 hours out of it.
On a different note, an iPad also makes for a decent external display for a cramped 11" MBA.
The psychological effect of this is surprisingly powerful.
So it's more like a cook who prefers an oven with a temperature knob over the flexibility and control of lighting and tending his own fire.*
* I say this a someone who definitely is glad not to have to kindle a fire to cook even the most elaborate meals, but who loves a good wood-fired pizza.