As a former owner of this light, the 60W version, it was great, but has some serious issues;
1. Lots of issues with the battery carrier for many people. I had to send mine back for repair.
2. You can only enter turbo ONCE after which you must turn the light off in order to enter it again.
3. In a warm environment even the low mode will get too hot.
4. Eats batteries fast.
5. Once you do a turbo run, you will need to allow it to cool down.
6. If the light gets HOT, you will want to turn it off, preferably take batteries out, and it will actually get hotter before it cools off, so it's out of commission for ~10 minutes or so.
7. Like all HIDs it needs to warm up.
Don't get me wrong, I like it, and I certainly don't regret buying one, but having had it, I can't help but to think LED lights are superior in most applications.
If an FF5 with active cooling, and carrying 8 batteries instead of 4 came out, I would grab one, but until then the FF4 just isn't practical to me.
As an alternative, I very strongly suggest getting an Acebeam X60, dedomed, and with a current bump. You'll get ~6000 lumens from it, and ~500kcd.
A modded RC40 would also work, but the price tag would be steeper, and output not quite as high.