i got an ergo tec recently. i like them. the claw clasps the channel and there are these two teeth that bite into the rubber squeegee blade (also, it is impossible for the channel not to be in the exact centre possition, which is cool)
as for the guy asking about hard and soft blades. there is no noticeable difference aside from durability. hard blades last about 10000 times as long as soft ones, which last you til about lunchtime (literally) before they start leaving faint lines on the window. and when you turn them around, the blade is worn about a cm in from the edge, where the blade has been bent.
so yeah, there is no need for soft blades at all. they should be banned. just companies trying to make more money i suppose. a hard blade can last me at least several days or even a good week (some guys make them last an ENORMOUS length of time). and all that about winter is complete bull