Pros: If you've ever looked for one of these in the states, you'll already know they cost more than *5* times what this thing sells for. That alone is the best "pro" going. :)
Now add to that the fact that each of the modes are *cumulative* and this timer trigger becomes the coolest accessory in my bag. Check it out:
There are four modes to use:
Timer (1 second to 99 hours range), Interval (1 second to 99 hours range)
Long Exposure (Bulb mode, same range)
Exposure count. They can be used individually, or in combination, depending on what you want to achieve.
For example, you can set the timer for ten minutes, set the interval for 2 seconds, and set the exposure count to ten. Press start, and ten minutes later, you get ten frames spaced two seconds apart. Press start again to repeat the sequence. The settings are stored for as long as the battery is installed, and the battery is manufacturer rated for about three years.

Cons: It would be nice if the sequence mentioned above could be set to auto repeat, but thats about the only functional con I can think of offhand. (So it gets a 4 out of 5)
Build quality got a three ONLY because the battery compartment is a little flimsy when its open, but how often will you have it open when you've got three years of battery life? :)

Other Thoughts: You'll need a wall wart (mains) power supply to take advantage of the really long timing ranges, but think about setting the interval to one hour, aiming the camera at a flower getting ready to open, then using one of the free video editors to join all the exposures together. Time lapse photography!

Bottomline: The unit also features a manual override with the usual half and full depress (though there is no soft stop between, just a really long button travel) and a button lock for bulb mode, etc. The nice thing is that the manual override doesnt interfere with any timing sequence currently running.
With the free shipping, decent quality, and huge price discount, how could you possibly go wrong?