There's good evidence that it's definitely larger, by quite a bit, than Pluto.

163

Since UB313 is decidedly larger than Pluto, it is now increasingly hard to justify calling Pluto a planet if UB313 is not also given this status.

139

It would be impolite to Pluto to degrade it to something less.

94

It is now increasingly hard to justify calling Pluto a planet if UB313 is not also given this status.

82