Missiles pretty much 'work well' at any tech level especially when you consider them against the capability of other weapons at early tech level... and main downfall of missiles early game is they're not as effective as missiles late game.... there is the resource consumption part to consider producing missiles, but providing you're not over flooding production elsewhere in your empire then missiles really should never get to the point where they're taxing your empires economy. If they are and it's not due to very poor RNG luck with resource discovery beyond your homeworld then it's time to re-examine some personal habits.
Beyond missiles, as others have said the other go-to is going to be railguns. Heck sticking with a Railgun/Missile combo works well throughout if you're happy to just roll with what works perfectly fine and aren't one of those people that feels compelled to use what is absolutely the best at any point just for the sake of it.
I would still argue that missiles are kind of "meh" early on, and an early start with low to no missile usage is often more efficient. Missiles do work at low tech, but their operational usefulness window is pretty limited when your engine tech advances, and they do eat up resources your arent getting back. Low tech AMMs in particular are nothing to write home about.
As soon as your engine tech advances and your ships are running new engines, those old missiles just got a lot less useful. Even at improved nuclear pulse, missiles are kind of iffy.
As an example, if your ships are 2,500 to 3k speeds at Imp Pulse, and your missiles hit % is around 35% to 40% on a 3k target, 43% (ballpark) at 2,500k, and your going to do about 4pts per missile. So, on average, your lobbing 3 missiles to do 4 pts.
Now, compared to comparable tech particle-3, 129k range, tracking 2500, your hit rate is; 92 84 77 69 61 53 45 38 30 22
or a rough tech equivalent railgun (15cm), same TS 2500, 32k range, and your looking at 69 38 6 for hit rate (x4) for 3pts.
So, are missiles bad? No, not at all. Are they efficient? Kind of.
Missiles are expensive, especially early. An average ASM 4 at improved pulse is using 1750 fuel, per missile. That doesnt sound like much, but with a ship carrying 54 of those, for example, thats 94,500 fuel in that missile load. That starts to add up. Multiply that by numbers of ships, and spare missiles.... yeah, that starts to become noticeable. Four destroyers have enough fuel in just their missiles to run one of my survey ships for a year!
That is why I dont think the are the
best weapon early on. They are absolutely useful since they have huge range, but they come at a cost. I dont think they are the best primary weapons early.
Now, once you have some more time and tech, and you have better warhead yield, more agility, more engine efficiency ect.; missiles start to shine. And its a must have before AMMs are really worth a damn.