Instrument training is considered to be the most rigorous rating. Before signing up for a ten-day instrument course, assess how you best learn. Some schools send a Certified Flight Instructor - Instrument (CFII) to you, in other cases, you travel to the school. In either situation, you spend eight strenuous hours a day learning, both in ground school and in the air. To qualify for your instrument rating, you need to pass written and flight exams and complete 40 hours of flight training. A ten-day course allows you to concentrate on one thing and frequently costs less than spreading your training out over time.
Professional Instrument Courses (PIC) has been sending CFIIs around the U.S. for longer than anyone else. You pay for an instructor to come to your area and teach you in your own plane or one you have rented. The advantage is that you learn in the comfort of familiar surroundings. The instructor brings a simulator and some of your flying time will be spent using that. If you have many distractions at home, this may not be an optimal solution, as you need to spend time reviewing after your instructor has left each day.
Going away to a flight school allows you to get out of your element, be away from your home life distractions and concentrate on flying. SPIFR in Michigan, Cactus Aviation in Nevada and Connecticut Flight Training all offer accelerated learning courses. Some schools include housing and transportation for a nominal fee and most assign you a dedicated instructor for the time you are there.
Some people may prefer a hybrid course, similar to the one that American Flyers offers. This type of course has a five-day online component, after which you go to school at one of its many branches for an intensive five days of instrument training. Alternatively, some flight schools offer what they call a finishing-up course. If you have already had some instrument experience and perhaps passed your written exam, the finishing-up course focuses on what you haven't learned and gets you ready to pass the flight test.
Before you invest the money and time in a ten-day course, be certain this is a way you learn well. Ten days may sound short and easy, but you will learn more during those ten days than you will for almost any other rating or license. It is an intensive experience. But once you pass and have that rating, the ability to fly without having to wait for clear skies and great visibility will be worth it.