Seamless terrain generation (Simplex Noise vs Perlin Noise)

So I've been looking around a lot to figure out how I can generate seamless terrain on runtime in unity and have ran into a question which seems to have a lot of answers; "What is the best/fastest algorithm to generate terrain with".

The closest I've come to a great answer is that Simplex noise is only faster for 3D or bigger dimensions where Perlin seems to be faster for 2D.

I do also wonder if there is other algorithms I should consider instead, and if I should use 2D or 4D noise as some sites talks about 4D being better for random seamless noise.

So basically I wanna know/ask what is the better solution and possible pros/cons with them for my particular usage, and if anyone can lead me in the right direction with the whole random generated seamless terrain thing, as I do wanna choose the "best" option for my particular problem.

Thanks a lot in return!

 

Shameful bump

 

As far as I know Perlin Noise can only generate in 2 dimensions and is always slower than Simplex Noise, no matter how many dimensions it is generating in. Simplex noise has the advantages of being faster and being able to generate in more than just 2 dimensions.

 

I'm pretty sure I came a cross an article yesterday showing perlin noise used in 3D and 4D and saying simplex was only faster in anything over 3D as simplex runs in N^2 where N is dimensions and perlin was 2^N so for 2D it doesn't matter as both are 4 but in 3D perlin is only 8 where simplex is 9, But i'm not sure how reliable that article was so that is why I decided to drop this question here, as well with the general question on how to generate it, that being 2D vs 4D noise.