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In considering lists, I'm finding myself over and over facing the same choice, just with different serpent mounted unit.
You could take a full squad of something with a proper exarc/warlock and a decent serpent, or for just a few more points you could get two bare bones serpents loaded up with half squads.
Offensively the more expensive option hits harder than the sum of its cheaper equivalents and may have extra abilities. But doubling down on serpents just makes a while lot more work for your opponents guns and grants tactical flexibility.
Now obviously once you get up into really high point totals you max out the FOC.
But what about when you aren't there?
Why, you stop pretending the game is designed for competitions, and start playing for fun. 40k is not designed for tournaments. Anything that can be swung by dumb luck is inherently imbalanced to the most gross degree. That's why I write a different list for every game, because davu serpents is boring.
He never said that 40k had to be pure competitive, he just wanted to know which option was more cost effective. Not to mention, the dude has to actually fork out $30+ per unit, so he has a right to ask which is more efficient.
That being said, it really depends on what your going for, your opponent, the scenario, etc. In Kill Point games, larger squads will kill more, die harder and offer fewer KPs to your opponent. In Objective games, almost nothing is more powerful than a scoring Wave Serpent that can move 36" in a single turn for last turn objective grabbing/holding.
Two squads can be in multiple places at once, obviously, and two WSs can put out a lot of hurt.
Unfortunately, I don't play enough Eldar to definitively tell you which is usually the better choice to go with, and I don't have enough games under my belt to tell from personal experience.
Generally people take minimum troops in wave serpents such as units of five dire avengers and such, As well as taking bare bones transports as well. When it comes to the rest of the list again it tends to be somewhat bare bones, such as 5 basic firedragons. Although you can upgrade in the right places for effect such as holofields on heavy supports and upgraded seer councils. Really it depends on your playing style but it seems people play quantity of the quality units. Sure my 1750 list has 8 tanks in it.
"Reached under the bed and pulled out a Converse and a beer, I appear to of developed the miraculous power to turn shoes into beer!.... or beer into shoes." - Fallen Autarch after St. Patricks day.
you can play quantity but even bare boned the waveserpents are high quality transports to begin with. Just equip them with the tools that you need, if you think you need that extra 12" to get you fds into position then take them and vectored engines if you want to make it harder to destroy your tank out right. I usually take spirit stones though, I don't like the idea of being stationary when I don't have to be.
Davu Serpents are never boring because have their own weaknesses (test at ld8 from the second casualty on troops comes in mind for example). In fact Eldar is not boring because it demands from it`s player to understand better the concept of moving in this game. And regardless of statistical luck , 40k is NOT a luck related game. is a game where the player can either depend on luck if his plan is about rolling a few dice in a certain moment or the player can choose to mitigate his dice luck in a statistical matter and use movement and tactical decisions to be the game breaking points, not the dice rolls.
Yes statistical deviations exists. but those deviations can be accepted in one game and deal in a fun matter. And this is where i agree with you. We always should play for fun.
The difference between me and clasical list builders is that my fun reside in having a list that allow me to use my decisions to win or lose the game and not having a rock scissor paper list that will autolose on certain enemy builds (foot orks versus Immo spam comes in mind )
that is a fun balanced list for me.
regarding OP question is how you mitigate the quality problems. those problems come from lak of dices to roll that allow you to get more deviations from statistic point of view. You have have 3 serpents with fully kitted avenger squads or 5 serpents with DAVU. quality and quantity. Roll good and those 3 serpents can be better than those 5 DAVU serpent. but play 100 games and you`ll see that those 5 serpents are statistically more efficient than those 3.
All resides in concept of target saturation. Every army can threaten a defined number of threats per turn. On AT side let`s say the enemy have 5 missile launchers on 5 units. he can damage 5 targets per turn. he probably will not manage that but the possibility is there. What if he had 4 missile launchers on 2 teams. he can have better results in damaging only 2 targets. But the other 3 serpents of yours are unscratched and ready to drop next turn in those devs head. this is for example the great improvement long fangs have over regular devs. but target saturation have to be balanced with AT firepower, high AT reliable capability to destroy (say mobile melta), anti infantry firepower, mobility, durability (the enemy is firing too).
There are a lot of factors in order to make a balanced list, a list that have a chance to fight against any decent player with another balanced list. And the fun is in players not in the list.
Hight elf and Craftworld Eldar army project pics heavy: linky
From everything I understand, 40k has only been taken seriously as a 'sport' since 4th edition. The rumblings were there in 3rd but it's widely accepted the game was too wobbly at that time and nothing was balanced properly. Regarding chess, the worlds #1 player recently declared the game "dead" and that "everything is just pattern recognition now". The only luck in chess is who goes first. Now if players went simultaneously... that.. would be a whole other kettle of fish.
It's also possible to have fun at tournaments, don't act like they are mutually exclusive.