Pinnacle Studio 9 and before use a rendering engine (programming) that has been fraught with issues. Studio 10, Liquid 5 and 6 use a rendering engine that is much more stable and uses the resources (Video Card, etc.) much better the the older studio products.
If you were thinking about it, you might wait a bit on Studio 10 to let Pinnacle/Avid work the bugs out. However, Liquid Edition 6 is an excellent NLE in it's own right and if you can afford it as well as the learning curve, it a great NLE and will most likely serve you better than the studio products.