i'd say i have around 2000 miles on it. maybe more or less, dunno cause my speedo cable is fried. would have more miles, but the car is down because of some valve train issues that i caused at the track.
for the durability i kinda look at it this way; even though price is the major factor, lets not consider that right now. many folks worry about it crapping out on em, motor quiting or whatever. what about the mech one, it can still crap out on you, bad bearing, drip out the seep hole, broke impellar causing it to lock up and no more spining the other accesories(big if), or whatever as well. either way you will have to end up changing it, one just cost more.
dunno if this is a good analogy or not, just my thoughts.