Italian is A BIT harder.
First of all:
people who choose spanish as second/third language are more than people who choose italian, so dudes saying to you spanish is harder - without knowing italian, anyway - are way more numerous than the other ones.
Italian is more difficult than spanish because:
- spanish writing system is a bit more phonetic than Italian one;
- spanish doesn't have particles like "ci" and "ne", while italian has got them;
- in past tenses, spanish have an only ausiliar, italian - like french - two: "avere" and "essere", so you have to know which verb uses in "passato prossimo" : wich verbes requires "avere", and which ones "essere";
- italian compounds verbes:
Suggerire = "to Suggest"
Suggerirlo/la = "to Suggest it"
Suggerirmi = "to Suggest me"
SuggerirmElo/la = "to Suggest it to me"
Suggerisci a me = "Suggest it to me only"
Suggeriscimi = "Suggest it to me";
- to make plurals in spanish GENERALLY you have to put an "s" at the end of the word. Italian requires more attention;
- stressed vowel in spanish are shown, in italian not.
Anyway, no matter wich one is harder/easier: both are lovely languages, as french and portuguese/brasilian too! :D
Spanish is harder in pronunciation of "j", "ll", "ñ", "g", "r";
Italian has only 3 difficult phonemes for foreign people: "r", "gl", "gn".
French would be difficult as Italian and Spanish.
In speaking conversation maybe it's easier (in french you can know the subject even if you don't remember the ending, because people always pronounce it "je suis Allemand", "je suis en train d'aller à l'école", while in Italian and Spanish you have to learn ending, coz they don't use to pronounce subject as often as French and English people do).
French orthography, though, has never been changed, so today it has a lot of obsolete letters.