Well I just sold my only two nGTLDs for a loss and I was happy just to get some beer money, so it would be fair to say I'm not a big fan.
I just can't see the upside for nGTLDs right now. I would prefer to spend my money on .com and .com.au, because I know I can make money in those markets.
If you're looking to invest in the new extensions, my advice would be to wait for the really good ones that are still in contention, all the best ones are yet to come.