Pros: - it looks so cheap it actually becomes cool :-)
- it looks so cheap you can leave it on the bike and nobody would steal it
- it really is cheap, money-wise

Cons: - it really looks even cheaper than on photos. It may be a plus, see above.
- the battery cover holds on only by hope. You put it over the battery and it is held only by little friction. But it is of no issue once you put it on the holder as it secures it (problem is only when you take it off)
- auto-off function on mine didn't work, so it eats the battery in a week

Other Thoughts: I didn't bother returning it when I found the auto-off doesn't work making it unusable for me (postage would be more than it's worth)

Bottomline: I probably wouldn't buy another.
They run some discounts locally from time to time here, and before this I had a wireless one (much nicer, even if heavy radio noise can interfere with it sometimes) with additional solar charging and therometer for about 11$. It was also much better looking. Much better value for the price. However it met with an accident, so I got the DX one as and even cheaper replacement.
Finally - If you never had one, get it. It's great fun for a month or so (after that it becomes for most people in most cases more trouble than it's worth, especially if you also have a GPS unit). And you won't feel the obligation to continue using it (because you payed much for it) after it loses it's spark.
And if after a few months you find out you're one of the freaks that can't live without it, you'll have some experience to get a better and much more expensive model.

Pros: The computer has a lot of functions. (Like 7-8 options).
Very simple to use and very simple to setup.
Seemed like it would be weatherproof.

Cons: Straps to attach it to the bike were a little stiff and hard to use, we warmed them with a hairdryer.
About 1hr after installation we dropped the computer from about 24 inches off the ground and the screen cracked (ruined the unit).
We dropped it on to gravel too not pavement or concrete. My son was quite disappointed.

Other Thoughts: Came with battery.
Bike computer unclips from the handlebars once installed.

Bottomline: If you are the careful sort I'd recommend it for the price but for a kid it will easily be broken.
I recommend if attached to a kids bike, instruct them NOT to remove it from the bike and attach to center of handlebars so it doesn't get knocked around.

Pros: Very inexpensive. Like most other units it measures speed, distance, average speed, etc.

Cons: The 2 button interface is very clumsy. The one page guide is almost unreadable. The unit failed after a week with a loose or intermittent connection.
It also uses a low capacity battery that won't last too long.
And the clock doesn't keep good time, it drifts a lot in just a little time.

Other Thoughts: For a few dollars more you can get something much better. Go to a local shop and get a Cateye Velo 5 or something like that.

Bottomline: It is good if you don't want to spend much money. But don't be surprised when it fails or the tiny battery goes dead.

Pros: Very cheap but usefull.
Everything, except the build quality is awesome, but what should we expect for cheap price? The build quality is OK, not terrible, in fact friends of mine think that the price is 3-4 times higher than what I spent..
but probably, it is because of deal extreme :D

Cons: has issue on my first test...
it shows only 0 (zero), my first tought were the cable.. but then realize that it is the connector problem...
the connector is loose, once I fix this, it works just like a charm

Other Thoughts:

Bottomline: it is very cheap, and working for sure.
I'm not thinking about accuracy (yet), just have it for some fun.