I own both the Paul chen practical chinese broadsword and the Paul Chen Water song (the red flexible chinese broadsword). These are both superb swords for the money you pay.
I use the flexible one when learning new forms or practicing complicated, dexterous handwork, or when doing any tricks with my sword (just for fun). It's safer and lighter and easier to handle.
I use the black model (the stiff, heavier one) for forms I know well enough to be confident I won't mess up and hurt myself. This sword when you buy it comes dull, but not really 'blunt' it could cut someone badly if you hit them with it. The tip on it also comes to such a fine point that it would easily pierce flesh and even bone if you stabbed with it, or dropped it tip first on your foot or something.
I also own another, second-hand Paul Chen kung fu broadsword, that I customized by polishing the blade to a fine finish, grinding a 4-inch (10 cm) blunt section to the ricassa (the area where the edge meets the gaurd); And sharpening the rest of the blade to a razors edge with a diamond sharpener. I don't use this one for forms, or practice, I use it to test my cutting skills. And to prove to all the people I meet who say that Paul chen uses bad steel, that they are dead wrong. I once cleanly cut a free-hanging ham quarter in two, with only one swing of this sword, bone and all. Boy that was fun. And it made all the people present who thought reproduction swords and any sword that isn't hand forged **** , step back and take notice.
You should ask your instructor which sword you should get; the flexible one or the stiff one, and then make your decision. These are both great swords for kung fu practice. One thing about the Cold Steel ones, is that they come razor sharp when you order them, not the thing you want for practice. I would advise against them.
I bought both my swords from this e-bay store: It's called "Grendels Cave" and they have fair prices, good shipping and a great selection of the non-japanese Paul Chen models. If you live in the U.S or Canada, this is a great place to buy from.
http://stores.ebay.com/GRENDELS-CAVE-SWO...displayZ2QQtZkm