Well the market cap doesn't matter too much now anyway because the volume condition (US$1 million of trade per day) is far from being met. Ironically it was the massive sell down in holding of the GDXJ in December that markedly reduced the daily churn.
I actually considered purchasing it earlier this year but the lack of volume confirmation was what scared me off. Obviously a good one to own if the US$ gold price starts moving with unmatched leverage really.