I evaluate Alekhine Defense as a promising one, with lots of options and complicated outcomes! And it's good for an Engineer to use the Defense since it is very challenging!
Alekhine Defense

I don't think it is sound. There are too many knight moves to really justify the defense. It is rarely used at top level chess and is mainly employed for the surprise value.

Alekhine's is fine. It comes and goes in popularity and is one of the defenses that people should know. The purpose is to bait white into creating a weak center by getting its pawns to chase you around. If played correctly, both players enter the mid game about equal, but due to its awkward look and its unposh standing, there are a lot of opportunities for players under GM status.
I use it occasionally mostly when my hatred of the Ruy Lopez comes to a head, and have so far had success in both correspondence (1800-2000 range) and live play (1500 range)
How do you evaluate Alekhine Defense? It is a sound one or just a losing defense whenever u use it?!