My .02: Go with the Dinotte 140L and forget about the cheapies. At the end of the day it's all about getting from point A to B safely. Install it on your helmet to give you maximum visibility to the cars behind the cars. Keep the rear light in constant flash to get (and keep) the drivers attention.

Also, you can do a search on the site for other info on rear lights.

All the best and ride safe,

Jeff