Sculpt is a beautiful, wireless keyboard. It feels more like a notebook keyboard than a desktop one, but personally I don't find it a problem. The function keys double as media keys, and the functionality is switched using an actual switch on the top right corner, rather than Fn key present in Microsoft Natural Ergonomic 4000.
The number pad is a separate entity with its own non-standard battery. You have been warned. Personally I put it on a shelf. It's handy that you can separate the two parts. Thanks to that Sculpt takes about 40% less space on your desk than the 4000.
Now... the wireless part. The keyboard comes with a teeny tiny USB receiver which is found underneath inside the battery compartment. Microsoft's decision not to use Bluetooth is... surprising. But, hell, I put the USB receiver in a USB slot. Then started typing. I first thought some keys need more force than others, as I'd hit a key and nothing appeared on the screen. Then I realised that when the hard drive is working, keystrokes are ignored. Nothing happens. I moved the USB receiver to another slot on the back of my machine. No improvement. Then I moved it to a slot on the side of my computer. The keyboard was within 80 cm from the receiver. IT DID NOT WORK. Or rather it worked, erratically. Sometimes the keystrokes would register 95% of the time, sometimes not at all, leaving me very frustrated. Finally I put an external hard drive with USB slots on top of one of the speakers (which is not really a spot for a hard drive) and when the keyboard was within 50 cm from the receiver it finally worked.
I ended up ordering a USB extension cable. Now, with the receiver within 30 cm from the keyboard it works perfectly. But it looks like Microsoft succeeded in inventing world's first wireless keyboard that needs a cable to work.
I imagine your experience will depend on your setup (perhaps if you have a computer with USB slots in front you can use one of those). For me, though, it's baffling. It smacks either of very limited testing in live conditions or of "will this do?". To sum it up, if you enjoy the idea of a wireless keyboard with a cable, by all means go for Sculpt, it's beautiful. Or just buy a Microsoft Natural Ergonomic 4000, regular USB cable, no hassle with batteries, not as sexy as the Sculpt but even more comfortable thanks to standard desktop-style keys.