Lake Bled has a totally different feel / appeal.
For us we feel Plitvi?ka Jezera is overrated.
If you go further into the national park area on the Southwest of Lake Bled, Jezero (Lake) Bohinjska - It is a much bigger lake, lots of wilderness, and more beautiful than Lake Bled. You can find it on Google Map and there are some nice pictures on street views. We like that area more than Lake Bled, where there are too many tourists.