Money:
When I was making this decision, I went with the fact that elixirs can't be pickpocketed or looted from mobs. Also, the prices of nightmare vine on my server are butal.
However, the market for pots is probably higher than elixirs, if you figure that 8 of 10 classes use mana, and all 10 need healing pots from time to time. When it comes to elixirs, the market gets more narrowed as some classes don't care about attack power, agility, spell damage, +healing, etc. Also, those elixirs last for an hour, while a pot can be used every 3 minutes.
Practicality for a mage:
A raiding mage would probably use a great deal of mana pots, and those mats are very easy to find. If you are crafting a bunch for yourself, you might want to go this route.
The sad fact is, you can probably make more money selling the mats. I'm happy to break even on my server, because I figure crafting can yield discoveries, and as a raider who goes thru 4 flasks of relentless assault per week, I wouldn't mind the extra convenience of making them myself.