Signal seems to make a great board; out of the two if it were me I would go with the Vita Rocker. But, I don't really ride park and don't have experience with either of those boards. I would just like to try a Signal haha.
The K2 VaVaVoom seems to be a good park deck, too.
If you like Mervin tech (like your Ollie Pop), check out some of the Gnu park boards like the girls Park Pickle or maybe the B-Street.