The Umineko art style gets endearing after a while. I thought it was a huge detriment at first, too, but the plot, music, atmosphere, everything else makes up for it. And by the beginning of the Answer arcs, I loved it for the personality it gives Umineko.
Just make sure you're ready to think outside the box and brainstorm hard when you're reading. It's good when you're reading, but it's godlike to hear the protagonist parrot your arguments or have an antagonist immediately strike down your theories.
Also make sure you're ready to read at least the first two before giving it up as boring, because Umineko is a case where the boring parts really drag on. But every bit of character development is worth it a few hours later when the plot picks up an explosive pace.
--
'But what a passionate guy! He must be Italian or something!'
KrahenProphet and Kana are on opposite ends of the Awesome Spectrum.