Most people i ask this question do not want to give a straight answer. They tell me that they are both influential people of the past. Why should i have to choose?
Even after they say that, they tell me that Tesla is a known fraudster, and Einstein developed the atomic bomb. How can you respond to this? Most people are taught this in school, and very few question it. The atomic bomb seems huge, 100 foot long lightning arcs on command seem tiny. But, this is because they don't know.
If you really look into these two characters, you find that one is a genius, and the other married relatives.
Albert Einstein
"Albert Einstein is a fuzzy haired crackpot" - Tesla
The real life of Einstein is so horrifying, no one believes them, except those who really looked deep. Further, the stories of Einstein are nice, sweet, and were created by some of the best propagandists. The deep truth is that Einstein was the guy they set up to hide Werner Van Braun.
Einstein was not a nobody, his family was actually very influential. They got the young Einstein a job at the patent office. Where he could see all the new things before anyone else.
Which makes it not strange at all that he plagiarized the Theory of Relativity. (Einstein is not known for creating any other theories. There is a refrigerator with his name on the patent, but he clearly wasn't involved in its design)
His first wife, a mathematician was rumored to have been locked in her bedroom, where Einstein fed her under the door, in exchange for her doing the math work on the Theory of Relativity. (Of course, the story is the other way around. And who knows)
Einstein divorced his first wife, and married his cousin. (This is what many people mockingly say is the real meaning behind "relativity")
And then the Ivory Tower Hierophants pushed many conclusions from several tests, that only very rich people with military contacts, could ever repeat. Basically, the Theory of Relativity has the most flimsiest evidence for it. And there are so many disproofs it is a tragedy that it hasn't been swept aside for something real to fill its place.
That the speed of light is not constant, is one of the easiest disproofs.
Nikola Tesla
Nikola Tesla has 100s of patents to his name. Most have been shown to work. But, like Tesla's Tower, nobody understood how it was supposed to work, and because they denied the Aether, never would. So, there are many patents that just baffle people.
Tesla loved to demonstrate his inventions. And many a newspaper reporter got to see them. And the propagandists put into the populations' minds that he was therefor a huckster, a con man.
Lets point out that the world record man-made lightning arc was a mere 110' long, as a substation melted down in the dry Arizona heat.
Tesla created 100' like lightning arcs on command. There isn't a physicist today that can do that, scam or not.
Just the Tesla Coil and the Radio transmitter AND the AC motor, things that are known that Tesla did, are HUGE inventions. Tesla should be in the list of top inventors, but he is missing from any official list.
And the piece de resistance is Tesla's Tower, which people assume was never completed, thus it was never proven it would work. However, Tesla built smaller towers and transmitted electricity miles away and lit up a town. (this is the time when Tesla broke the power company's generator) This is all recorded, documented, many people saw it and wrote about it. But, everyone believes the story that he never actually 'proved' it would work because the large tower was never finished.
Tesla vs Einstein
If you compare the propaganda told to children in school, Einstein is absolutely, hands down, the winner in who was the most smartest and most important physicist. But if you actually look at the facts, the known things, Einstein helped create a bomb (maybe), but Tesla created almost everything that makes our world modern. Electricity, radio, robotics and even harnessed the power of the Niagara Falls (without building a dam).
Almost everything Tesla invented is still used today, in almost its original form.
No one really uses Einstein's theories. NASA doesn't even use them when communicating with Voyager, the fastest man made object. (The having to adjust the clocks on the GPS satellites can more easily be modeled with Lorentz contractions, but we will never know, because we, the little people, have no access to any part of that system.)
Tesla was known for making outrageous claims about the future and what would be invented, however, such it is with most inventors. But, Tesla made thousands of working inventions and received patents on more than a hundred. So, we should forgive him, and if we were there, and knew all the things he did create, would see that he knew what he was talking about. (imagine if you went back in time and told people you lit up your house by flipping a "light switch")
We owe Tesla a lot for what he did, what we knew he did. And if we ever get back to Aether theories, we will see he did even more.
In the future, we will know Einstein as a plagiarizing, scam artist who was into young, inbred, women and liked to wear women's shoes.
All most people know today is propaganda. Stories made to sway the public away from the truth.
And, when asked, Tesla or Einstein, most people do not know that they were polar opposites. That the two cannot exist in harmony. Ones' theories disprove the others, and the other's inventions disprove the first's. So, really you have to choose. And there is only one choice after you get through the propaganda.