So, when I first switched to a mac, the IDE that fell in my lap was Coda. I was absolutely amazed at what this wonderful IDE app could do for me. I had heard a lot of people talking and praising TextMate so I decided to venture over to TextMate and see what they had to offer. Ever since I've had these two IDE's on my machine I have always been switching back and forth between one and the other. Sometime's it's a coda day and other times it is a text mate day.
One complaint that I have about Coda is that there is no code collapse and the keyboard shortcuts, such as ending HTML tags. So, I hope that these features will be in Coda's next version. Coda does have a lot of advantages, such as direct FTP access/editing capabilities and the terminal window available right in the application.
NetTuts+ put together a great article about 20+ tips to optimize Coda for maximum use. If you are a Coda user, I would definitely recommend checking out this article. Additionally here are a few other sites that point out Coda tips and benefits
For now, Coda and TextMate will just have to be friendly neighbors on my machine because I just can't kick one out.