Summary: Portraits - nice even light, way better than built in. Kids/Animals - critters in the "wild" (NY woods), pets, kids. Architecture/ruins - where legal! Takes a much better picture of an interior room than built-in -- more even, less glare. I said heavy as a Con. OK, I'd like it to weigh nothing, but, realistically, it's worth it. It's in my bag so I can take it wherever I take my camera. So, it's not too heavy...
Pros: Consistent Output, Durable, Easy To Use, Even light, Fast Recycling, Powerful Output, Quiet, Versatile
Summary: This flash is so powerful I often have to adjust the settings to get it to put out less light. Having to much light is a great problem to have especially when you can easily tone it down. I've always had issues with not enough light or terrible looking pictures from the built in flash.
Summary: This is a great flash and a must-have for any professional photographer. I shoot weddings and prefer to use natural light but when fill flash it needed this is the flash I turn to first (and I have 3 others). It's a great flash, especially when bounced. The kit does leave a bit to be desired. I thought I would use the diffuser more, but it tends to fall off if I move too quickly.