Be sure you're taking into consideration the average height people will be viewing your taillight from their cars. If you're standing directly behind your bike it may looks dim, but crouch down and view it like your in the drivers seat, much brighter down there. Also there is a plastic tab on the backside of the housing, there is supposed to be a rubber dampener on that (should look like a small piece of rubber hose. That piece not only helps out with vibration, but it also pivots the taillight housing up some.

To try and answer your question, I bet the same Chinese factory makes the cheap eBay unit you bought and the overpriced Clear Alternatives unit.

Does the Clear Alternatives unit have built in turn signals?

 

If you have CLear alt's brand and want to sell or swap to stock give send me a pm.

 

Possibly. Mine does not have the integrated turn signals, it is brake and tail light only. It definately uses normal globes, not LED's.

 

You're spot-on there IMHO! Other vehicles at different heights wont see them so well as the standard bulbs!

I had LED indicators on the rear, but have now reverted back to the original.
Admittedly I preferred the look of the LED ones, but for me now safety comes first.

As you say with LEDs you need to be in line with them to get the maximum brightness in view. Even looking at them slightly to either side of the centre line they're not so bright as the original bulbs.

 

Mostly that is the case. The Luxion LEDs I put on my bike are very bright off axis. Here is an example. Note the even with a camera flash they're still bright.

 

That has very little to do with actual brightness and are more due to the fact that the Luxeons have a lense fixed to them giving them (I believe) a 110 degree viewing angle...

Same for the LED module that haknslash and others including me have used... The 10 LED's there each have an individual lense behind the outer shell (could be integrated into it, dunno...) that give a good viewing angle and it can be clearly seen from any vehicle height...

 

I'll chime in here - the LED turn signals on my mototech undertail are very directional and because of the undertail design they "shine" about 30 degrees to each side. I never realized how invisible they were untill I rode with others who thought I was not using my signals at all.
I added an Ebay clear alternatives knock off. It is focussed faily narrowly also, but the combination of the undertail signals and the integrated tail light gives me decent coverage.
I have not seen a real Clear Alternatives tail light. If it really gives a full coverage pattern it is probably worth the price. Checking the threads here no one has indicated that is the case