You can't really just make easy comparisons like that unfortunately. You have to compare one specific steel to another really. Steel can be hardened to greater or lesser amounts because of the carbon in the steel. This is true of what we knife-heads call "carbon" steel but also it is true of stainless. There is lots of carbon in that too if it's any good.
The addition of elements like nickel or chromium etc to the steel are what turn the "carbon" steel into high-carbon "stainless" steel. There are a million different combinations possible when formulating steel. "Pumaster Steel" found in older Puma knives is one example of a classic good old-school carbon formula as are Schrade's carbon offerings and those of other quality companies.
When it comes to stainless three commonly used grades are 440A, 440B and 440C. 440C is the "hardest" one generally. It has a higher carbon content and so it can be more easily hardened to higher levels as measured on the "Rockwell Scale". The harder a knife the longer the edge should last theoretically. There is a trade off though and an important one at that. As hardness and carbon content increase so does the brittleness of the steel.
In real world use some "toughness" and minute flexibility is also a good thing in a hard working knife. A super-hard blade that snaps in two but remains razor sharp still does you no good. The near-microscopic terminal edge of the blade is also more prone to snapping off if it encounters something hard than would be a softer blade. Either way your knife will dull if you try and cut hard things. Also whatever you sharpen your knives with has to be significantly harder and more abrasive to be able to remove material quickly and easily from extra-hard steels. A diamond-hone is really the only thing that chews up 440C in my experience.
On the other hand 440A (and the stuff we call "carbon steel") has a lower
maximum hardness (most steels are never tempered to max levels: makes em too brittle) and so can be easily and quickly re-sharpened and re-sharpened. Keeping your knives re-sharpened after use keeps them always ready. No knife will chop up something and stay sharp forever but you could argue that 440C holds an edge "better".
To really complicate matters for us it seems the reason Schrade always just said their stainless knives were made of "Schrade+" steel was not because it was a secret formula kryptonite-steel no one else could figure out how to make because it's easy to melt down steel and analyse it's composition. They said "Schrade+" to imply that mistaken belief but also so that Schrade could change up their choice of blade steels whenever they liked and the buying public would remain blissfully ignorant. They did do this too so I have read. Schrade+ was 440A, 440C, 420HC, 440B I think at different times. In the late nineties I have read Schrade even admitted to having to "tighten their belts" and drop quality of steel in their production knives.
Really Rockwell hardness number is what speaks to edge retention, strength and brittleness. If you do a great job at tempering 440A you can achieve hardness levels of poorly tempered 440C and achieve a perhaps "better" (and even harder) knife from the "softer" steel. A huge part of the cutler's art is in the tempering of the steel to uniform hardness through the use of heat and cold.
All of this goes together to mean there are no cut-and-dry answers to "Which is better?" or "What is the best?" It depends on too many different variables and the preferences of the user. Here's a good link if you want to learn a bit more...
http://chemistry.about.com/cs/metalsandalloys/a/aa071201a.htm
Super-short answer: Carbon sharpens easier (than 440C or even 440A) and holds a wicked sharp edge but with stainless it's a bit harder to get that razor-sharpness in the first place.
the YEARS IMHO 
I will say from experience that the older blades + new sharpening technology is WAAAAAAAY better!!!:thumbup: