Looking at Windows 8 Tablet, need advice from Owners

I am really interested in purchasing a Surface. I am currently doing some Windows 8 app development and am looking forward to building applications for my Tablet.

The issue I have is which Tablet to get. The Surface with Windows RT is very nice, and probably my choice if I am ok going with a RT flavor of tablet. But the idea of pro and being able to install Visual Studio, Photoshop, etc on a tablet to make building and testing apps more native sounds like a good idea.

So far I have considered the HP Envy x-2 and the Surface Pro.

Surface Pro has not released yet. Does anyone have the HP Envy x-2 and can you give me your thoughts on it?

I tested it in the store and the only issues I have are the lower screen resolution, the larger size of the screen, and the atom processor. The battery is hard to argue with though, with 14 hours total while docked. The Surface Pro is estimated to get 5 total. Mobility is a issue for me. But the 1080p screen will help a lot with development. The Surface Pro supports a pen which hopefully has a high resolution. Has anyone tested the HP with a pen?

I was also considering the Dell XPS 10, but it has not shipped yet.

Any feedback would be appreciated. Thank you.