I'm a solo operator, so no employees to blame. I bought one last spring. I don't believe I'd be without one of some type and this may be the best available on the market.
That being said I've gone through three motors in one season already. I also folded mine up pretty good hitting an object head on more than once and was able to bend things back due to the decent metal used to make them. I strongly recommend keeping a bungee cord on the machine so if it breaks in the field you can hold the shoot open to finish the area since they just go limp and flop closed. Some of my properties are quite large and it can be a drive back to the truck. I also keep a new motor on hand so I can swap it out on site. Fairly quick and easy job to do and about $45.00 at Napa.
If you remove the unit for any reason (mulch kit, bagger, etc.) zip tie the loose wires out of the way. I learned the hard way by stuff/wrapping them out of the way. They made their way into the deck belt/pulley even so, and I lost about a foot of it. Only way to purchase that new part of the harness is to buy the whole pedal assembly for around $150.00. I ended up splicing and putting non-oem blade ends on to the motor to make it work and save the dough.
My experience is that the plastic gears are stripped more often then not by running the chute in a position other than full open or full shut since this is a metal chute. Many times I'll have it approx. a 1/4" open to keep clippings from going in a flower bed but will still allow it to disperse, mostly on a second pass situation. If your in a ditch or near an obstacle and bump the chute from the bottom up your the proud owner of a new motor in many cases.
I've had several manual style chute blockers, including a homemade one, and at least one had conveyor type rubber and another was a thick hard plastic. One of the next things I plan is to purchase a piece of thick rubber and to make a hinge bracket for it so it flexes so there is less impact on the motor gears.
The slots in the metal chute IMO do nothing but make it look cool. They plug up instantly. The advertisement that some of these chute blockers aid in blowing things off hard surfaces IMO also is a stretch to say the least. So don't buy one thinking it is the end all for this.
If it hasn't been mentioned already there is a similar system using a manual foot pedal/cable that I believe is called Grass Flap out there as well.