For me personally the pre op diet was actually harder than the post. I agree definitely you can also do lean cuisine, weight watchers, etc...I also agree i'd stay away from the slim fast that is a lot of sugar. I like the EAS ones personally but everyone has different tastes. I also did the fiber choice tabs for quite some time and they did help a lot.
Good luck to you all that are coming up on your surgery!!! You will not regret it!!!