Battery life on the 1st gen Surface Pro wasn't so great... something like 4-5 hours.
Yesterday I upgraded my Surface RT to a Surface 2. (took advantage of BestBuy's trade-in program). I had tweaked my RT to improve performance and was fine with it, but the more I tried using it as my primary tablet (I have 4 other tablets), the more noticeable those laggy areas became. I haven't had much time to play with it (tons of updates), but the time that I've spent with it has been quite enjoyable performance-wise.
As for whether or not a Surface 2 can meet your needs, you'll need to take a personal inventory of the applications you use and plan to use on it. If there aren't any or many legacy apps on that list, then I think you'd be fine with a Surface 2. I frequently attach an HDTV to my RT (and will with the 2) as a 2nd display, and the experience is terrific. I assume it will be even better with the 2.
I've been wrestling with the practicality of "legacy app support". On the one hand, theoretically it sounds great... run any Windows app that I want. But giving it some more thought, in practice, it would not be so great. In "tablet mode" (no keyboard, just touch), using the legacy apps that I'd use would be virtually impossible. In "netbook mode" (keyboard cover, mouse) it would be possible but would require additional storage (for apps) and performance would lag. In the end I concluded that a Surface Pro would be the "worst of both worlds" for me... the limitations of a tablet with the systems maintenance of a desktop. But that's me.