Welcome to the Forum!
The Sony HX-1 is a good camera, but not up to the consumer level DSLR cameras. My biggest complaint concerning the HX-1 is that it is really not as good as the FZ-28 in terms of low light level shooting. However, in fairness the HX-1 has some pretty unique features such as handheld panoramas, or doing a single burst of 10 shots with a single shutter click. I did not think those where features that I would use all the time.
So, IMO the choice has to be made with regard to the kind of photos that you take and your style of shooting. I think it would be wise to do a small analysis of:
What kind of photos do you like to take?
Is the the size and weight of the camera a factor in your opinion?
With that information, we can come to a better conclusion as to whether the FZ-28 or the HX-1 is the better choice for you. Have a good day!