I get the most variety of min-able coins with my GTX 1070 rig vs my RX 480 atm. AMD excels with ETH and Zcash but It doenst look like they can sustain previous profitability over the long term (but who knows). I think its smart to have one of each. Which is why I have 2 rigs, one GTX 1070s and the other RX 480s. Just my 2 cents.
Honestly, for mining, I wouldn't invest in nVidia, never ever, unless the price diff is like 10$ with an equal AMD card. Don't get me wrong, I love me some good nVidia power, but for the price, it's not worth purchasing nVidia for mining. Also, typically, nVidia don't get first hand access to GPU mining. Heck, Claymore hasn't even done anything for nVidia for ZEC and the party's over anyway.
Especially in current times, zec is going down the drain and ETH's difficulty will grow again once switching back.
@OP: just keep in mind that before you ROI 1400$, it will take you a lot of time, so be sure this is money you can afford to loose. If not, I'd suggest not getting the whole 1400$ in mining equipment. Buy some BTC with that, some say it'll reach the 1K...hey, it's as good an advice as any.
For instance, with 3x RX470 8GB, you'll hash ETH at roughly 80Mh/s, ZEC at 450H/s. You will not have immense earnings.
Don't buy RX480s, go for sapphire RX470 nitro+ 8Gb. They're cheaper and run almost as well.