CAT

You can't exactly weigh both exams on the same scale and decide which one is easier/tougher. There are a few differences between the two exams:
Mode and pattern of exam:
CAT - Computer based. Calculator included. 100 questions. 3 Marks for Correct answer. -1 for wrong answer. 3 hours. 1 Hour each for 3 sections. Sectional timings exist. IIFT Paper Based. No Calculator. 100120 questions. 1 or 0.75 for a correct answer (IIFTs discretion). And for each wrong answer, 33% (of that question) marks are deducted. 4 Sections in total. 2 Hours. No sectional timings. Sectional cut-offs exist here too. Sections and what they ask from a student: I'm only going to talk about the points of difference when it comes to the three sections:
VERBAL:
CAT verbal predominantly has inferential questions. Doesn't test specifically on vocabulary or meaning of tough/rare words. (I. e. you don't have to by-heart the meaning of 1000 words to sit and ace CAT verbal). IIFT Verbal tests more on fact-based questions in their RCs and a lot more importance on vocabulary, when compared to CAT. DILR:
CAT DILR has a logical edge to almost all its questions. Fairly rare to see a CAT DILR question that is purely computational. IIFT DILR is a lot more computation-based (as opposed to having a logical edge) and not having a calculator makes it that much harder. So pick and choose sets where you can do the computations easier. Quants:
CAT Quants in CAT 16 took it to another level which might make it look as though IIFT quants is a LITTLE easier, but generally they both are of the same difficulty level. IIFT Quants is along the same lines as CAT Quants with the exception of IIFT 2016. If you have prepared well for CAT Quant, you have prepared well for IIFT Quant as well. You will get only 20 or so questions here. Try to nail as many as possible because they give most marks. IIFT also has a GK section that you have to separately prepare for. They have sectional cut-offs. The sectional cut-offs for the GK section were as low as 2 or 3 marks, but if you do not clear the cut-off, you will not get called. So do not plan to skip an entire section. Strategy for taking the exam matters just as much as preparation. So please solve the past 23 years IIFT Papers with the time constraint (2 Hours) and formulate a proper strategy.