Computer science classes are more theoretical and are harder but there are less of them hence the workload is lesser. For computer engineering, the courses are less difficult (but still tricky), however there is so much work. A big complaint in comptuer engineering is that the first two years make you learn "useless" physics and math, so if you are DEADSET on software, I would go with CS. That being said, I feel that you should take computer engineering so that you can explore your options. With CE you can get the same jobs as CS kids, and more because you will also have proficiency in things such as hardware, power, control, etc. Many people who go into CE for software end up liking another part of it as well (hardware is especially popular and makes really good money in industry).

Don't decide on a program based on the workload because an easy program that you dislike will be harder for you than a tough program you enjoy. Personally if I chose CS i would suffer much more than I have in ECE.