When I was first introduced to Pyfa I of course mentioned that I already used EFT, and that it worked fine. Little did I know the power that Pyfa had in store for me.
One thing I just love about Pyfa is that I can make a fit, start a new one, close the old one, close the program, and all my fits are still there. Pyfa keeps all of your fits saved, and allows you to look at them as you look through the list of ships you want to make a fit for. You can see on the image to the right here, I have 14 Machariel fits, 6 Typhoon fits, 3 Tempest Fleet Issues fit, etc, etc. All of those are saved automatically! Another thing that I just love, is the layout of the app itself. It shows all the information you could possibly need when fitting, and best of all that "EHP" button next to the explosive resistance icon. That switches your fit to "raw HP", showing how well your ship really tanks against incoming damage. Not only that, you can make your own custom damage pattern template to put against those resists to see how well your ship tanks against various types of damage.
One thing I constantly use Pyfa for is setting up fits
for new characters. At the beginning of the summer I made a brand new Factional Warfare pilot, and was specifically building it to be an awesome frigate pilot. So I added that character to Pyfa via the character editor with it's API key. Once I had the fit done, I would edit the character's skills to see what skills would get me more damage, speed, or tank to that ship with the very minimal amount of training time. All I had to do was open up the Character Editor, and edit the skills as I saw fit. After that, I could then I could see how it reacted with the fit I had. Needless to say all of this was more than helpful when dealing with my pilot.
So there you have it. That's Pyfa. There are still a few other features it has, but not any that are any different from the EVE Fitting Tool (EFT). I'm sure after all the time I've been using Pyfa they've added such features, but I wanted to at least show everyone what I use for ship fits. If you are more than happy with EFT then by all means keep using it, but at least consider doing like I did, and try it at least once. :)
You can download Pyfa Here At EVEFit (Sourceforge site is the old site, with an old version)