This is always a “lively” topic! For the newbie considering getting into the Cobra environment, give your pros & cons for what a starting kit should look like.
This kinda reminds me of “Building a Gaming PC for X-dollars” and seeing what justifications people give for choosing what they did to stay under a cutoff price point. 
I like 18M’s for no reason other than I can spread out the ques if I want to.
My recommendation almost always is going to be go with 18M’s until you get to a point where you are routinely shooting racks of 36 individual shots or more. Then it may make sense to pick up a 36M.
I prefer stocking up on 18M for the following reasons:
I’ve been using Cobra gear since about 2016 or '17. I have (17) 18M. And really only now have I considered getting a 36M because, using my own advice, I’m to the point where my shows routinely have at least 36 individual shots at a given location. That might be my finale racks or my CraigCo racks for single-shot 1.4pro stuff.
We own a semi-pro firm and we have 72-18M’s (9V). We always preferred 18M’s since in our history we had reeled in/out tons of FireOne/Starfire/Salzman cables. We just didn’t want to get into the slat cabling biz. We’ve used Muxbird’s on occasion for some series wiring, but mostly we just place an 18M where we need it. We kept to 9V since we store our mod.'s in containers in Texas, and even Cobra advised us the lipo’s would degrade in the heat. We pre-board and pre-wire effects directly to 18M’s vs. using slats.
Wow, that’s a lot of single shots!
Anyone ever give you shit for transporting things that are wired up?
My reply to such a question would be that it’s essentially no different than not being wired since there’s no electricity being applied. At which point, some asshole would say, “But there’s still a battery in the system…” and then I’d have to reply, “Yeah, but there’s a switch that physically breaks the circuit coming from the battery”. At which point the asshole gets all assholey and tries to argue the point by getting further and further to the bounds of rationality. 
Yes, a bunch of PU guys would go crazy commenting on this. In the real, we treat each construct as a set piece with named EX#'ers in our BoL for transport. Most don’t even do that with their slats in transportation.
New guy here…just jumped back into the game after taking a 20 year hiatus…
I went back and forth with Happiness, Bilusocsn, and FireFly.
The more I read, the more I found that Ignite/Cobra/Mongoose/FireTek was the way to go.
After deciding that if I was going to come back, I was going to make a quality purchase, I needed to stick to the bigger brands and ensure that I had support available, a warranty, and large enough customer base that if I decided I no longer had time and needed to give it up, the resale market was solid enough.
I started with 1 - 18r2 Controller and 1 18M Unit. Since then i’ve picked up 3 more 18ms and i’m glad that i’ve gone this route. I agree with statements above that unless you’re doing 36 shot static racks or other larger shell/single shot setups, then the 36/72 makes sense.
I really like the 18’s for the many options listed above in regards to flexibility, mesh node, and cost. While Cost per Cue is slightly higher, its replacement cost is much lower.
So far i’ve been really happy with just 18m units and I could see a 36m in my future but for now this is my current setup!
