Are we to assume through the context provided, that this poll is for the specifically linked designs, or if the poll is meant to inform a general design aesthetic?

If the former, I'd say balloons, as there's very little other grouping indicators present in the individual comments (and the page design looks pretty flat in general).

If it's the later, we'd need to consider the design of the elements of the page and the relationship between various headers and text elements before a good decision could be reached. As well, more color/size/contrast elements in a potential design may force the balloon elements to be of a much higher contrast themselves, which could ultimately overload the page.