LogoGuppy : I have always been a fan of the mixed font style, but it takes a good pairing to pull it off. The thing here was to find a serif that had a reasonably 'round' letter 'o' to match the sans-serif 'o', many are more oval or condensed in nature.
But I feel what you are saying, I think maybe the serif is a tad too light/thin. Just looked at a bold version and this sits better with the sans, which is 'Verlag' by the way. :) The serif is MrsEaves...
This made me laugh. :)