Obviously ETH has clearly established itself as the leader between the two. However, I did like some of the technical papers I read about ADA. At the time I was reading them, nothing was functional...I prefer to have something more tangible so I passed at that time.

Diversifying is really the best bet. Develop a strategy for splitting your money between the two. This way, if one turns out to be a much better play, you will be in the game either way.