If I may add my 2 cents..... Firstly, I presume when you are asking about engine braking, you are actually describing downshifting into a lower gear. If so, here are the facts:
1. Down shifting does not add any wear on the clutch because the clutch is not engaged when you have already down shifted. In fact, there is hardly any wear on the clutch at all as you down shift because you are not loading the clutch since your foot will not be depressing the accelerator (different story if you are circuit racing and doing a heel/toe manuever.

2. As long as your engine speed (RPM) is not excessive. Which means it is not beyond redline, you will not wear out or hurt your connecting rods or any internal components. Maliban nalang kung magkamali ka ng downshift from 5th into 2nd at high speed. (Walang gamot sa katangahan pag ganyan).

3. It is always advisable to use the engine brake more than your footbrake on general road conditions because the vehicle is always more controllable when you are decreasing speed through your gears rather than through your brakes. It is a known fact that it is harder to steer a vehicle into the proper direction when the brakes are being applied.

4. The concept of placing the vehicle in neutral as you decelerate gains you very little in fuel efficiency but has the potential of diminishing your absolute control on the vehicle's speed and orientation. Find your gas savings elsewhere! Remember that as you downshift (e.g. before reaching an intersection) even if you are in gear, you wont be stepping on the gas so what consumption are you trying to improve?

Having said all of this, perhaps you will consider the use of the engine brake on more occassions. As it should be the case anyway. Hope this helps.