The title says it all!
Which of the two is in your opinion harder to enter relatively speaking.
Vote in the poll and explain in the comments your reasoning to your choice and if you have experience in entering either one or both you can lift the differences in them both regarding growth.
I've done both and my answer would be, it depends. I find the barrier to entry is much easier on the B2C side if your product is free as a lot of people aren't willing to spend money. On the flip side, if your product is paid, it's typically easier to get buy-in on the B2B side, from my experience. There are obviously exceptions to both, but that's what I've found in general.