Image quality ...Blue Ray discs vs 1080i HD mpg disc???

I am mulling over whether to buy a Blue Ray writer to create discs made from my digital videos.

Has anyone compared the difference in IQ on a blue ray disc and a 1080i HD disc made from the same HD video file?

In practical terms are blue ray discs overhyped mpg2 HD discs or is there a perceptible difference?

Thanks for your help!