I'll disagree with just about everyone else here, and here's why.
We've been vaping for over 8 years now and followed it's evolution quite a bit.
I mainly use the Melo 2 and my Lemo at this time and love them, but also have the Atlantis and my daughter just got the Melo 3 (with her Pico, which she absolutely loves). I have a OBS Ace coming (waiting eagerly for it, to use with the RTA, but does take pre-built coils) and I've heard nothing but good about the OBS Crius (RTA only).
I have other types too, including the Lemo (RTA) and a couple of drippers (RBA), so my knowledge is from trying the three types of tanks variants. Including my wife and daughter's Nautilus (standard and the mini).
And the verdict is... the Melo 3, the 2, and the Atlantis can all use the same coils, and
they are ALL FINE... what it comes down to is choosing the right coil type for you... I tried the Kanthal, Titanium and Nickel from Eleaf, then tried the Vaperasso ceramic. But there is a
HUGE selection for other coils available that are compatible.
Between those I've tried, the Vaperasso had better flavour, but from coil to coil, depending on liquids, they can clog up fairly fast.
So I started rebuilding them with Nickel and cotton and they are great, even better than the pre-made ones.
The Nautilus is a bottom choice, gotten on "recommendations" and used for quite a while, but the truth is, once my wife and daughter switched (first with a Kanger Aerotank, then the Melo 2), their Nautilus have ended up in a drawer and never used since. And I'll even say that whenever I would use their kits with the Nautilus, I NEVER enjoyed it, always weird taste, didn't like the airflow (found it poor). Heck, I got mine (Melo 2) first, and both of them would constantly "steal" it and pout about being stuck with the Nautilus until they got their own.
Your Melo 3 tank will be just fine, just make sure that you set the settings correctly, and I do recommend using temp. control (which once I started using it, loved it and wouldn't go back to Wattage mode). I prefer Nickel to Titanium as it taste metallic to me and I find it very temperamental. I have yet to try Stainless Steel though, but I only just got a mod that has SS capacity.