Pros: Easy to set up...well there is no setup really, just insert the flash, and off you go.
The flash sync port is extremely useful. I use mine with the Yinyan BY-28ZP bought from DX. The hot shoe on that flash is a little finicky, so the pc-sync port is really nice to trigger that flash.
The hot shoe works fine with my 430EX.
It's a Seagull - good brand

Cons: Perhaps due to rough handling during shipping, the unit came defective. I could feel there's something loose/springy inside, and it didn't work as described - will only trigger when I tap the outter case.
So I pried open the back cover, and found that one of the leads to the photocell came undone. Nothing a little soldering won't do though.
Does not really work with TTL flash metering, as the first pulse will trigger the slave. In other words, normal mode is too fast for TTL, and redeye mode is too slow for TTL. So you have to use manual flash, which isn't really a problem, because you expect to grab quick snapshots when playing with multiple flashes anyway...there's setup time.

Other Thoughts: I contacted DX reporting the defect, but no one answered. I think DX has out-grew its capacity, and that really compromises high quality customer service it used to have eve a year ago.
Since the redeye function isn't really used for me, I wonder if I should've gotten a cheaper version.

Bottomline: Very nice little flash slave trigger!

Pros: Wonderful trigger hot shoe Easy to use and fast to set up. Just slip your flash unit in the hotshoe and start shooting.

Cons: The red-eye function is a bit problematic. It's just a simple delay but you have to experiment a little before you get it right. TTL flashes can make it trigger prematurely but, as you will be using more than one flash, you should probably turn TTL off.
This is possible with canon camera and MANUAL program.

Other Thoughts: I have used it on a flash CULLMANN c20 for analogic camera and with my canon 450d... and it work very well.
The prelamps for ttl measurement don't work very well with cheaper version of seagull hot shoe

Bottomline: Even if you already have a wireless trigger set, this unit will allow you to quickly and inexpensively add another flash unit to your arsenal. If you don't have a canon camera, you can also buy the even cheaper version, since you probably won't be using the red-eye feature much anyway. But with canon camera... it's indispensable

Pros: Very nice addition to your photographic equipment. Easy to use and fast to set up. Just slip your flash unit in the hotshoe and start shooting.

Cons: The red-eye function is a bit tricky. It's just a simple delay but you have to experiment a little before you get it right. TTL flashes can make it trigger prematurely but, as you will be using more than one flash, you should probably turn TTL off.

Other Thoughts: Doesn't work with older flash units with high trigger voltages. It's also a bit hard to set up if there is too much light. The only problem with the build quality is that the rear panel pops out. Nothing that a drop of super glue couln't solve.

Bottomline: Even if you already have a wireless trigger set, this unit will allow you to quickly and inexpensively add another flash unit to your arsenal. You can also buy the even cheaper version, since you probably won't be using the red-eye feature much anyway.

Pros: Works perfectly on my Canon 430EX. Sensitivity is adjustable which is absolutely great! This means you don't have to trigger it straight on for it to fire. I use my Canon 400D's built-in flash to trigger my 430EX with this slave trigger attached. Adds heaps of flexibility in taking flash photography. Much much cheaper than buying an off-shoe flash sync cable.

Cons: Shoe is a bit thin to fit into my Canon 430EX's plastic stand. Causes the flash to wobble a little. Nothing major and not a showstopper.

Other Thoughts: Good for experimenting with flash photography.

Bottomline: Must have if you have a 430EX