I haven't, but I've looked into it. The problem is that you have to understand what you will be losing. Burning fat is nice, but what will happen to the muscle? Your body still needs protein to maintain muscle mass, and obviously needs it to increase muscle mass.
There are formulas all over that outline protein intake, but for building you generally want to be in the 1-2g/lb of body weight. For maintenance, Lyle McDonald claims you need about 1-1.5g/lb of lean body weight. If you drop your protein considerably, understand that you may lose muscle mass, or you may not see full results from your workout because your muscles are not getting enough to repair themselves.
I understand the idea behind ketogenic diets, but I have a hard time accepting their validity for people who do body building. For us, you walk a fine line when you cut, because if you do it wrong you can lose muscle.
I also understand the desire to look good for swimsuit season, but are you building/bulking for size, or for just looking good at the beach?
My skepticism lies with the differences of body chemistry. There are ways that can work well for most people, but cutting carbs is usually an effective way. I wonder whether the ketogenic diet is benefited by the low carbs more than maybe it's acknowledged.