Okay, quite a tricky question. There are several points one have to consider:
One basic thing: Whiskey and tequila might have a particular taste, vodka normally hasn't (as it is distilled several times and other reasons). The range of whiskey notes and aromas varies more than the tasting notes of vodka.
4 things you should consider, when you compare:
1. the taste of the drink, neat
2. the taste of the drink, mixed with x
3. the "state" or "high" of drunkness (drinking red wine gives you a different feeling than drinking vodka)
4. how well can your body manage the poison, how well do you feel the next day.
I guess you would have to find out about that first. Taste is subjective, there are people who love tequila but not because of the taste but because of a bad experience.
But the answer to your question can only be:
You can only find out yourself.
I'd say it's all about the same in strength. But I would go with brandy, it tastes way better and is more sophisticated.
Forget the strength, forget the taste, drink Vodka. It's much cleaner than either one of the other two mentioned above. You can make it taste however you like by the mix you choose.
All are going to be around 80 proof which is 40% alcohol by volume. There are a few vodkas and whiskeys that can go as high as 100 proof being 50% alcohol. Makers Mark (technically a bourbon) is 90 proof which is 45% alcohol. Wild Turkey 101 is 101 proof just like the name would imply. There are also a few 100 proof vodkas on the market.
As for as taste no one can tell you that. It is really up to the individual. I like vodka in martinis, whiskey in Manhattans and a good blanco tequila in margaritas. That is just me though and your sense of taste may vary.
All of these have a range, on both strength and taste. Mostly, they're all in the 40%-ish range, so the alcohol content is similar. You may find some cask-strength whiskeys that approach 50% abv.
Tastier? No way to say. There are nasty vodkas and there are great ones -- same goes for tequila and whiskey.
Alcohol content vary, and taste is objective.