If you're looking to get the stats and the touchscreen, there are some nice convertibles out there now. They don't detach fully like the SP, but they're still pretty sick.
I just bought myself a computer in the past few months...the stats, screen resolution, etc are all up to par with the Macbook. SSD hard drive, decent RAM, nice processor, super light, etc. More ports than MBP. The screen flips around on a special hinge so that it can be a tablet, or a computer, or anything in between, really (ever wished you could move your laptop screen closer/further away without changing the angle of it? It has a touchscreen and a digitizer in the screen so that it works with the n-Trig stylus, just like the SP3. It was cheaper than a MBP or an SP3 (it was not cheap, mind you, still $1k or so, but it was cheaper).
There are actually several convertible tabPCs out there that I would 100% pick over the MBP. Apple hasn't really updated their laptops in a while, and not only are PCs catching up, but the touchscreen aspect is far better and makes a far bigger difference than I anticipated.