There are more similarities than differences among these 3 English proficiency tests TOEFL, IELTS and PTE. There’s no doubt that the historically leading test TOEFL is facing some good competition and even less conventional one like Duolingo, an app based learning program which I personally use to brush up my French!
The main similarity among the TOEFL, IELTS and PTE tests is that all test proficiency in reading, writing, listening and speaking English skills. In addition they are pricey (US$160-250) depending on the test and location. Thus, determining if these tests are necessary is step 1.
In regards to differences, the length and format of the test differs with TOEFL being the longest at 3.5 - 4 hours, creating a challenge for some students. Both the IELTS and PTE are closer to 3 hours long. Another key difference is the format with some relying 100% on computer testing while the IELTS adds handwriting and personal touch with one-on-one speaking session - normally scheduled one week within the main test. This one-on-one colloquial conversational test may seem more realistic than the TOEFL where the student responds to 6 questions into a computer microphone after reading and/or listening to the questions. Additionally, the actual content of the tests which can be general and/or academic, yet the TOEFL tends to include primarily academic subjects like in the reading area, where it only includes textbook passages. Finally, the IELTS seems to ask questions in varied formats (fill in the blanks, multiple choice, etc) while both the TOEFL and PTE seem follow exclusively the multiple choice format. In sum, the TOEFL and IELTS seem interchangeable - it is a matter of personal preference once it is determined that the university requires the test for admissions.
Regarding a recommendation, I would recommend that you determine if you have a strong preference with any of the issues above since that would tilt the decision. If still undecided, you can always take sample tests to determine which one you do better and feel more at ease.
