Warrior Elixirs seem to be the most popular type of attack potion, and yet they are the most expensive one. They cost 5k mesos for 8 minutes of 12 ATK. Yet ciders cost 1k mesos for 5 minutes of 20 ATK (yes, that bug where it only lasted 3 minutes was fixed). However, many still choose to get the warrior elixirs only because they can stack 100 per slot of inventory. While "use" inventory is at a premium for many classes, there are still many good reasons to use ciders instead of warrior elixirs.
1) They're cheaper - Over a timespan of 40 minutes, you will have spent 25k on warrior elixirs and 8k on ciders. The warrior elixirs are more then 3x the cost and for less benefit.
2) They provide more ATK - Sometimes the extra 8 ATK can make the difference between 3HKO and 2HKO which can greatly boost exp/hr.
3) Much easier access - It's a lot easier to get access to Showa Town to buy ciders than to get access to NLC to buy warrior elixirs. This is especially true if you normally train in Aqua or Ludibrium and don't have an NLC mule.
1) Impractical for accuracy starved classes - Yes, ciders reduce accuracy by 5. This is only a problem for warriors, brawlers, and perma-beginners, though. If the 5 accuracy won't make a difference between 100% hit rate it might be a good idea to use ciders.
2) Takes up more "use" inventory - Only one cider is allowed per slot. For classes that need more use inventory than others (NLs are the primary target, gunslingers slightly less so), ciders might be a bad choice.
So, why do you use warrior elixirs instead of ciders? I prefer ciders.