It is fairly the same thing. And faster/quicker is a relative term. I have seen some low end mtb brake levers where the body was plastic develop a crack in normal use in the area just past where the adjusting barrel the housing inserts into...this does not typically occur with Brake levers further up the hierarchy made from metal.

The pivots and bushings in lower end shifters and derailleurs tend to wear quicker causing an inability or difficulty to dial in adjustments that last for any decent length of time. Where as higher end components with their better materials and designs (materials more resistant to corrosion, better forging such as cold forged parts vice hot forged or stamped steal, ball bearings instead of bushings, etc.) have a tendency to be easier to adjust/maintain and other than cleaning/lubing tend to require less headache inducing maintenance in the long run.

Often the design from a higher end component is trickled down to successively lower end components over the following years after the design first comes out. Often a change is made such as material or fabrication methods to be able to offer the general design at the lower pricepoint.

Sometime things can work the other way as if I recall correctly Shimano first introduced dual pivot brakes on their 105 line and subsequent to their acceptance in the market did they added it to the dura-ace and ultegra lineup. (I cant seem to find a source to back this up).

up to a certain point higher end stuff tends to be easier for a mechanic to install and adjust. That magical point where there are limited returns on investment could often be seen between Campagnolo Record and Chorus parts....they often were the same part with a slightly different aesthetic finish but chorus was offered at a significant savings over record. Some versions of Dura Ace and Ultegra were the same way....though shimano liked to experiment with their dura ace line over the years creating more frequent backwards and forwards compatibility issues with other year models of dura ace parts...which supports the idea that the top of the line is not always the best choice.

Take a look at how a cheap low end shimano rear derailleur attaches to a frame, and compare that to how the mid to high end derailleurs attach to the frame....both should work, and both could work; but given regular use and no crashes which will be functioning better in 100 miles/1000 miles/5000 miles?

I can understand the point being nebulous.

-j