Not recommended for beginners just switching over from smoking.
The "BEST" of anything is what works for you to keep you from smoking. With that said I have over 100 different atomizers and there have been a couple improvements this year worth noting.
The 24mm Nalu from Vaporesso is impressive.
It comes with a hollow 510 center pin for squonking. What I also like about the Nalu are the windows and the elongated bottom airflow raised tubes. Though the Tsunami has deeper wells and the bell isn't as tight as the Nalu.
510 Drip Tip
Single or Dual Coil
The 24mm Tsunami Plus from Geek Vape is Fantastic.
It comes with a 510 center pin for squonking. Instead of an elongated raised airflow it uses two round bottom airflow pipes per side. You can also find the original Tsunami without the glass windows and 22mm versions.
510 Drip tip via adapter otherwise wide comes stock.
Single or Dual Coil
The Pharoah RDA has the best posts of any RDA I have ever seen and the bottom airflow is fantastic. Unfortunately it's not convertible to squonking. So...if you don't want to squonk and I really don't see why you wouldn't, then the Pharoah would be a great choice. But if you ever go squonk, it is hard to go back to dripping. And given this year has seen several squonk mods and one for less than $50, it really doesn't make sense to drip anymore. Go Squonk.
Both of these RDAs use the velocity style posts which are an improvement over the old three post style but all of them and I mean all, drill the threaded grub screw holes too damn deep resulting in sharp edges where you wire goes through distorting and/or cutting your wires. I really wish they would go to clamp style posts on these like the Pharoah and I would really like to see 30mm versions.
Both of these have bottom directly under coil airflow which is far superior to side air flow or offset bottom airflow.
There are also newer Kennedy versions that look identical to the Tsunami. But pay close attention to the posts, you don't want an older three post style Kennedy. And none of the Kennedys come with squonk pins. Though if you have a drill press, you can precision drill a sub to 1mm through hole in a copper or brass 510 center pin very easily and turn them into a squonker. Leave them in the atomizer base, attach to a block with drilled and tapped 510 hole and center punch the screw tip very carefully and precisely with a fine pointed punch, brad, or carbide scribe and then use exceptionally light drilling pressure. Precision drilling SS that small is possible but takes a LOT of patience and a very good bit and press.
Since Temperature Control was invented I really don't see a use for any other type of mod. If you start with a disposable and want more, go straight for a TC mod. And make no mistake a TC mod will show you the faults of an atomizer quicker than a VW or mech mod. Both of these picks work extremely well with TC and high VG. Stick to single coil until you perfect your build techniques. A dual coil atomizer needs each coil to be balanced fairly well. This allows for even heating. If the coils are not balanced, one side can run away from the other causing temperature spiking and the output of bad by-products albeit still safer than smoking but still, the point is to reduce risk. Balancing coils is more than just side to side same length of wire total, the wrap spacings have to be balanced as well and I can tell you just looking with the naked eye won't work. You need a FLIR or IR sensitive camera. Crank the mod to 600F, do not wick and do not juice. Use a camera, try the one in your phone and turn off the lights. Some work some don't. Fire your mod and you should see the coil glow. If you can then you can balance a multi coil build. Gently spread the wraps until all coils glow the same amount and at the same time. If they are way off then you may have one more wrap or longer legs on one of the coils.
Unfortunates and what not to look for:
The trend with velocity style posts unfortunately continues. While this style is better than the old three post design it is not as good as those used in the Pharoah RDA. The problem with the velocity style posts is China always drills the threaded hole for the grub screws too deep leaving a sharp edge that cuts your coil wire legs when you tighten the grub screw. You expect a coil post to capture your wire not cut it. Even under screw posts are superior to these even though they tend to pull your wire when tightening the screw but at least they don't cut it. The clamping style posts are the bomb. Clamping style has been and always will be far superior to through hole and under screw style posts. There are at least three different types of clamping style, "postless", "notched underscrew" and "clamp underscrew". I have no idea why China can't figure this out.
Any side air flow RDA. We have known for years that bottom air flow is far superior to side airflow. Really these type RDAs are a genisys style RTA without the T, in other words a tankless genny. I have no idea why China keeps coming out with these.
Also be aware of mock bottom airflow RDAs. If you look closely at the build deck you will see sir slots built into the side edges not truly directly under the coils but offset to the outside. It's true these are better than side air flow but still not the best.
All the information contained in these pages are only the opinions of the author and the author is not an expert at anything.