tinyE: NO! XD Play around with Science Mode 1st! You jump into career mode and your head will explode. You need to learn how to crawl before you can learn how to walk. :P
cw8: I jumped straight into career mode and learned everything the hard way. :D It's fine hehehe.I think the only difference is money. You don't really have to worry about money at the start until you start building monster rockets which costs lots. But by then, you'll be doing missions that payoff much more than the rockets you build.
For me, the big difference between Science and Career for beginners is that you don't have some of the tools (like the orbit planner) at the start of career. And those tools are very handy, AND used in the tutorials, so doing without and having to unlock them feels a little harsh.
IronArcturus: I was hoping KSP would show up in the Fall sale, but I never saw it...
It's a pretty recent release, and they're still adding (free) stuff to it, so I don't think you'll see many promos for it in the coming months. Especially since it appears they don't want to play the DLC game yet (lower your base price, but sell full-priced additional content to compensate)