SNAP

Some basic pointers:
SNAP stands for Symbiosis National Aptitude Test. It provides admission to the 15 Symbiosis Institutes. Some of the premier colleges which one can apply for through SNAP include SCMHRD and SIBM. So how does SNAP fare in comparison to CAT. To start with, SNAP is considered to be relatively easier than CAT. The type of questions asked is also not wildly different preparation for CAT. Creates 80% of the groundwork needed for SNAP while CAT has MCQs and subjective questions, SNAP only has MCQs. So if the worst comes to worse, you still have a 1/4 chance to get marks in SNAP versus the subjective questions in CAT. This matters, since one question could be the difference between you and your dream college.
To conclude, SNAP and CAT are gateways to top colleges in the country while CAT fives entry into 150+ institutes, SNAP is for the 15 Symbiosis colleges in India which provide with an MBA degree. You need to research to figure which course suits you best. Some courses, such as the MBA in infrastructure management or business analytics are niche courses which have a lot of scope but are not talked about that much. Always apply for all the exams, you never know what might work for you. From an exam point of view, in case you are a candidate who feels that cutoffs will be a constraint in your admissions process and are able to manage time well, SNAP is your type of exam.

Here is a list of exams in the increasing order of their difficulty:
ATMA (the easiest, gave once, many of the questions were wrong. Very poor standard of the exam. Score 98+%ile).
MAT (I personally felt that the May 2017 exam was a few notches easier than the September 2017 version of the same. Scored 99+%ile).
CMAT (did not give it till now, but from what I've heard, this is another speed test, so questions are easier. Tad above in difficulty level from MAT).
NMAT (another speed based exam, will appear in October this year. Although there are no negative marks, one must score 215+ out of 360 for a sure shot convert into the prestigious NMIMS).
SNAP (harder than NMAT though the difficulty level is almost same as that of NMAT. Harder on the list because of the GK section as well as negative marking).
CAT (will appear this year, no need to tell why this is at the bottom where the most the toughest reside).
XAT (a stick higher than CAT, XAT is perhaps the most difficult when it comes to management exams. Partly because of its higher level of Quant and LRDI and partly because of its decision-making section).