Go to CEF Connect and look at their current premiums to book and their 52 week avg. You'll see they are both selling above their annual average. NCZ is right at 10% and that's a bit too pricey for me. Any little stock market pullback and these premiums disappear incredibly fast. Both have been mainstay's in my portfolio since 09. Those years have taught me that high premium to book can hurt you quickly.
I also own both for the past 3+ years. I have a 40% gain with dividends included, am very happy about it. Recently just went positive on the unrealized gain...finally, after last year struggling all year to get above where my average price is. FINALLY!!!!!!!! It pays to hold through thick and thin. Picked up 11% in dividends last year and now a capital gain...not bad.
Yes it underperformed the SP500, big deal. 30%+ would be nice to capture if you're fortunate, but if I can get 10% every year for the next 20 years I'll be right as the mail, brothers!