What Is The Difference Between Mino Hd & Ultra Hd Flip Mino HD 2nd Gen VS Flip Ultra HD, Whats The Difference?

Flip Mino HD 2nd Gen VS Flip Ultra HD, whats the difference? - what is the difference between mino hd & ultra hd

http://www.amazon.com/exec/obidos/tg/detail/-/B0023B14TK/ref=ord_cart_shr?_encoding=UTF8&m=ATVPDKIKX0DER&v=glance

http://www.amazon.com/Flip-Camcorder-Generation-Minutes-Brushed/dp/B002R5AM7C/ref=pd_cp_p_2

What is the difference between these 2 camcorders?

Is it worth it?

Thank you!