This is just my own personal opinion, so please take it for what it's worth.
I think this could be yet another example of proving John Bogle's point that, over time, most actively-managed funds won't beat index funds. Or at least that, over time, it shows that passive index funds can be just as effective as actively-managed ones.
I'm sure you know this already, but VGTSX is a fund of funds comprising of Vanguard's Pacific, European, and Emerging market index funds. Contrast this with VWIGX, comprising of a total of 6 fund managers picking a diverse range of foreign companies that include Korean shipbuilding (Daewoo), Brazilian energy (Petroleo Brasileiro), and German engineering (Siemens).
From what very little I can tell, they aren't bad picks, and yet, the past performance will show that not only is the index fund keeping up with the actively-managed one, but more recently, it's actually out-pacing it! Look:
Also notice that the trend lines are similar, which suggests that the fund managers haven't really made too much of an impact into the fund's overall performance (besides the small but compounding gap in slightly under-performing)....
Of course, past performance is no guarantee of future performance, but as a simple comparison between an actively-managed fund versus its index cousin, the result is still hard to ignore.... This is especially so when you consider that we haven't even factored in the (relatively low) ERs yet!
Again, this is just my personal opinion, but given the choice between these two funds, I'd sleep very soundly at night going with the index fund.