We get this question often and it depends. Typically though 3-6 meals a day is what to shoot for. Some people are able to make either one work by simply modifiying calorie intake. Depends what kind of person you are. Do you like to eat smaller more frequent meals or bigger meals but less often.
If you have a very busy job or don’t take much time out during the day the 3-4 day plan is probably the best for you. If you have all the time in the world and like to graze throughout the day than 5-6 meals a day should be your choice. Both have been explored for gaining or losing weight and both are effective. Just make sure you are hitting your daily calorie goal on a consistent basis with either one you choose. Good luck.