Having recently graduated from Teaching House's CELTA course in San Francisco, I can say with complete honesty that it was a very rewarding experience. I will always remember the friends I made on the course and the students I had the honor of teaching over the 4 weeks.
The schedule was packed on a day to day basis, filled with lesson planning, teaching, observing peers, receiving/giving feedback on teaching performance and sitting through valuable input sessions from the tutors in the evening on a variety of teaching strategies and topics (including how to find a job after the CELTA).
The course is very challenging. I had to say "no" to friends' requests to go hiking/have lunch on a weekly basis because of lesson planning and projects that we had due every week. Having a part-time job on the course is not feasible and is a recipe for burnout (although, a couple of trainees did work a job about 8-10 hrs a week - but it was much more stressful for them, and it showed.).
The tutors (instructors) gave consistent, constructive feedback on the content, framework and delivery of the classes taught by the trainees and made every effort to support the trainees by answering questions, offering advice and engaging the trainees in conversations about their own experiences teaching abroad.
The classes we taught were multi-cultural and the students were (for the most part) eager to learn and have their English critiqued.
I've come away feeling confident in my abilities to take on a classroom, either in the U.S. or abroad, and put the new skills I acquired on the CELTA course to work. I definitely recommend this course to anyone serious about becoming a teacher, whether as a career or just for a year!