I own a Samsung Series 5 Ultrabook. I don't want to bother looking up (or flipping the device back as I type this) the exact model but it basically has got an i5@1.7Ghz, 6 GB of RAM and Windows 8 (I like it, suck it up).
I can confirm that the device boots up disturbingly fast - either from a cold boot or from Sleep. I didn't time it but it feels like ~15-25 seconds. That gets me to the Welcome screen of Windows, and I can log in instantly. But if I try to start Visual Studio right after booting, I can definitively tell - from the LED - that the 5,400 drive is a problem. Right after booting, as Windows is, I assume, starting the various services and stuff, I can really feel the pain. I don't feel that on my main PC, which has got less RAM (4 GB) but a full-fledged SSD where the OS resides.
I paid 500 euros for that Ultrabook (Amazon repackaged). And for that price, I'm happy as a clam with that PC. If I allow something like 30 or 45 seconds for the session to actually completely open, the thing is blazing fast. A 7,200 RPM drive would drain the battery quicker (I have something like 6 hours of autonomy if I'm just coding - compiling from time o time - or just web surfing). I'd rather have a 256 GB SSD, but the price of those rose 30% in the last year so that might have put my PC around the 800/900 euros price point which, to me is not worth it.
This is not an advertisement or anything, just a direct feedback from a rather happy customer understanding the pros and cons of the technologies vs the price.