Ultimaker does have a bigger build volume,

I would personaly prefer ultimaker 1 or ultimaker 2 if you don't need the second nozzle,

As i aint completely sure about the quality of the parts from Wanhao, Ultimaker should have a longer life, atleast i think that.
I don't own either of the two, so take my advice not that highly rated.

0.1 vs 0.02 ? Ye kinda you will feel it, But it isnt that crazy of a diffrence.

It kinda depends on where you live and how much you wanna spend,
I have a Makerfarm but if Ultimaker had the price dropped when i bought mine i would have probably bought Ultimaker,
It doesnt support ABS but still, its a great printer, very stabile.
But thats also due i live next to the Netherlands (Belgium)