Which pronunciation of 'either' is preferred?

I pronounce 'ei' in 'either' like in German (so, like 'I' in English). This is natural for me.

But I've heard people pronouncing it as 'eee', so which version is correct? Or maybe both are correct?

Answer

Both are correct.

Ee-ther /ˈiːð.ə(ɹ)/ tends to be more common in the United States, but it would not be wrong to use aye-ther /ˈaɪð.ə(ɹ)/.

Whichever way you choose to pronounce it, you should not have trouble being understood.