Just my personal experience.
I've never had a PC laptop that suspended/resumed nicely. If you see people walking around their office with their PC lids open, this is why. Around here, suspend/resume/dock/undock are the leading cause of windows crashes and hardware failure (all dells, but I've literally NEVER seen a windows PC suspend and resume correctly over the long-haul). On top of that, hibernate is a complete fail.
The mac, however, is fantastic. I can close the lid and leave it sitting there for a whole day then still open it and it is ready to type before I have the lid fully open. I honestly can't tell you how valuable this simple feature is, you have to experience it.
Also, when you close it, the light stays on solid for about 10 seconds before going out. What it's doing is dumping the contents of ram to disk--then it goes into "Suspend". The thing is, Hibernate is "Auto" and "More Magic". Nobody knows this unless they have had to use it, but if you yank the battery from a suspended mac then replace it and turn it on, it resumes to where you were, magically reverting to a Hibernate you didn't even know you had!
Now, I thought this was all because of OSX, but after buying my mac I put windows on a Bootcamp partition and loaded the Bootcamp drivers. My WINDOWS partition now acts a lot like the Mac. It has a pretty darn reliable and quick suspend/resume!
Honestly I can't tell you if the difference is hardware or software, but if I was going to get a new windows laptop PC and had any choice in the matter, I'd get mac hardware and either dual boot or run Windows in a VM.