Which is the best country to study?
It depends on each candidate. Normally speaking for a 'good' student (one with a reasonably good academic background (preferably with a four year degree) and willing to work hard for GRE/GMAT/SAT and TOEFL, USA is the best choice. The main reason is the financial aspects doesn't matter at all as plenty of tuition fee waivers, financial aid and part-time job opportunities (First 9 months on campus and afterwards off campus). Also almost every student manages to find a job and stay back in USA after the studies. Moreover US degrees are considered as the best in the world in terms of future job prospects.
For students who can afford little more money and not interested in taking the pain of competitive exams like TOEFL and GRE and would like to settle down in India or Middle East Australia and UK are really good choices. The only drawbacks are no financial aid available for international students and future career prospects in UK and Australia are marginal.
Recently, Ireland is being proved as a wonderful choice for students with limited financial resources and average academic backgrounds. 'The Celtic tiger' has had the largest economic growth in the recent times (even higher than USA) and plenty of job opportunities available for qualified candidates. Also the sandwich programs (courses witch contains paid practical training) are quite helpful for the students, who does not want to tax their parents much.
Also we have been exploring lots of new avenues like Canada, Germany, Switzerland, Cyprus etc. for aspiring students and should be decided based on each candidate's priorities like intended major field of study, financial resources, career plans etc.
How tough are TOEFL, GRE, GMAT and SAT ?
Except TOEFL other tests are some extend YES... TOEFL (Test of English as a foreign language) is just a test to measure your listening reading and writing skills in English. Basically TOEFL is aimed at students come from Non-English speaking countries like China, Russia etc. As far as Indian students are concerned, most of the students study English since from their schooling and most of them find it as a cakewalk. Earlier TOEFL was a paper-based test and we had many students scoring 'perfect' score (677-678) in TOEFL test. Though most of the universities require a TOEFL score from 550-575, a 600 TOEFL score is always helpful in terms of admission & visa and very much achievable. In the recent times our students have averaged 640 in TOEFL Test.
In GRE, GMAT or SAT, apart from hard English you will be tested for your quantitative and analytical skills. Those with good vocabulary and quantitative analytical skills may find it as easy going and others will find it as a Herculean task until and unless they really put their efforts in preparing for this examination.