I believe Spanish is easier to learn. The letters in the alphabet always have the same sound no matter the position in a word. For the most part, with the exception of slang terms, words don't seem to have multiple meanings as in English.
I suppose if one learns a language as a child, with so much time to listen and speak before learning to read, it doesn't matter. But if one is choosing a language to learn as an adult, certainly with limited time for an outcome; a language that is easy to pronounce and spell would be the best choice. Once you learn to pronounce the letters, you can write and spell without error, any word you hear! Spanish speakers don't their spell names for each other, they just repeat the name.