IELTS is better. If you are looking for studying in any place in Europe but the UK both of them are okay. If you are going to the UK you should take IELTS and not TOEFL. If you are going to the US both are okay but I recommend TOEFL in this case as it is much easier and suitable. TOEFL is American, IELTS is British although both of them recognize all accents of English American, British, Australian and New Zealand

IELTS