My first bike was a '72 CB750. I had rode dirt bikes plenty before getting that bike. From little XR200's and 250's on up to big two stroke bikes like the IT465 (now that was a fun ride, would probably give my old K2 a run for it's money). In any event, the bike was great for a first bike for me. It was a little heavy but I quickly got used to that. Once moving the CB750 handles beautifully. It handles very smooth and predictably in the turns, as others mentioned. I've had many times scraping my pegs and throwing sparks on that bike and even when I gotta lift my leg way up to keep my boots off the ground I still feel comfortable and in control. Also, I'm 6'4" and 185 lbs, bike is comfortably sized for me.
As for the price, I think $700 is ludicrous for that bike. For my K2 I paid $100, gave a used set of Warn Dana44 hubs, and did the labor on rear brakers on a Blazer. Finally I cracked the trans case near the sprocket on that bike, too much powershifting I think. I bought a '71 CB750 K1 for $700. Bike is mostly complete, nice paint on tank and side panels, chrome is half decent, only light pitting on some pieces. Engine is insane. Power comes on around 8000 and it pulls to 12000. It ran rough when I got it but all I did to get it running nice was spray some carb cleaner into the carbs, never even had the bowls off.
Anyhow, go for it if you like the bike, but I'd get that price down by at least half. $700 should get you at least a bike you can hop on and ride, or an immaculate bike that just doesn't run.