Microsoft surface 2...
The surface 2 pro has the above but will run lr ps if needed. Has the options of up to 8gb ram and 512gb internal storage.
So those are better for in the field then an ipad.
I've had a look at the original Surface, I wasn't terribly impressed. I looked at in the Microsoft Store in a local mall, where I was one of four customers in the store (we were outnumbered by employees 2:1, and none of us bought anything). Four stores down is the Apple Store, where somewhere between 80-100 customers were filling the space, with at least 25% of people walking out the door with a new purchase). The dichotomy was not a unique occurrence - it's that way every time I happen to be at the mall.
Yeah the microsoft store is not like the apple store but thats like comparing bestbuy and office depot on a saturday. Microsoft still has a much larger user base and the appeal is enterprise first consumer second so yeah apple will be busier and microsoft can be had at walmart so the consumer is spread out more.
Anyway the value of the surface 2 or pro if you want to run programs is this tablet has a 2k point pressure stylus, 1080p full rgb screen with more antireflection. Backlit type covers and a docking station for home if need be. I own iphone 5s, ipad 4, mbp retina 15 but still think the surface answers the need here. $449 is great for review, edit, backup. Ipad does not offer that. Macbook air costs more.