Article from i-studentglobal.com says;
"The answer really depends on you; what kind of learner you are and where you want to study. The question of which is easier is largely irrelevant as both tests will grade you accurately according to your level of English. TOEFL may tend to favour more abstract learners as many of the questions are multiple choice whereas IELTS may be more suited to concrete learners as it involves memory recall. The face to face speaking section of the IELTS may be daunting to some candidates who would be more comfortable speaking into a microphone.
Finally, it may be necessary to check that your chosen institution accepts the test. Although both are accepted at more than 6,000 institutions and organisations worldwide, so there is a fairly good chance you will be able to use either, it is always necessary to check beforehand."