I'll would say both boards are good, but I wouldn't say the UD3P is nice-looking at all! The colour scheme is abysmal! Still, it's an ugly beast and manages to push chips further with it's measly 6 phase pwm, while the MIIF has trouble with quads near 500fsb with more than twice as many.
For your needs the MIIF should be more than enough and it's a nice comfortable board to work with with lots of fan headers, voltage and temp monitoring options, and once you get to know it and can be tweaked a fair bit to run nice low voltages.
I still have my MIIF and I loved the features and the look which is what sold it to me. Unfortunately I felt limited by the board in terms of getting the most out of my Q9650 (read way back in this thread), so I felt my only option was to try the UD3P which loves high fsb and DDR1200+ speeds. Might give the MIIF another try now I have my GSkill PI9600 but I probably wouldn't benefit a great deal. I'm kind of holding onto it as a backup, and I wouldn't be too disappointed if I had to go back, it's a good, nice looking board which should perform well.