i am using giffy.
I know it's been a few months, but I'd like to add my two cents. As a student, I've used flowcharts for studying and presentations, etc. Maybe it's just because I've used it the most, but I do prefer Lucidchart since it gives free accounts to students and it's really easy to use. Here's a flowchart I made for my rhetoric class. Also, it can come in handy when you want to open Visio documents on a Mac.