one of the motors stopped working the second day, ...
596603
one of the motors stopped working the second day, I had just got the hang of flying the darn thing and wham....motor stopped, which is really disappointing.
522969
I ordered a set of these, and after installing, it was apparent that 2 of them were bad. All they would do was shudder around, and one of them had a slight burnt odor to it. I contacted the seller, and they responded a day later. They had me upload a video of the problem, which I did, and shortly thereafter, they responded stating they were going to refund $25 of the purchase.  I liked the way the motors felt and looked quality wise, so I decided to order another set (hoping for better luck). They arrived yesterday, and I tried installing them today. 1 of the 4 motors received this time was bad. So, out of 8 motors purchased, only 5 actually worked. I contacted the seller again, and responded shortly after stating they will refund another $18.

I have yet to get them in the air, and to be honest, I am rather nervous about trying them out. Hopefully the bad ones shipped are not an indicator of how they will survive once they are airborne. The ones that work appear to be very smooth, and a lot quieter than the really cheap motors that came with my initial build kit.

The seller has been good with communication, but I can't recommend any product 50% of the product is dead on arrival, and 25% of the next order is also dead.
2458693
One of the clips broke on day 2. The other two are still working but I'm afraid because I have to be careful now.
2197404
The motor in the first one didn't work at all and it took about 3 months for the second one to go out. Save yourself the heartache.
4962663
Opened it up, powered it on, it had a broken motor on one of the props.
2509689
Great price and comes with all the tools you need. Just not sure about the quality of the motors. 2 days later and 1 is already out. :'(
1162712
One of them has stopped working after 2 uses but the other works well.
3016833
I had that problem too. Open it with a Phillips screw driver and check the wiring on the motor. One of wires broke off on mine and I just soldered it back on. Now it works great.
4004396
I will change this up a star or two depending on the replacements, but my first two I ordered were both inoperable.  The first one had a broken switch that had no tension to it, the other just didn't do anything when switched to "on."  Overall quality of build I would expect from something I bought in a dollar store.  Buy with caution.

Edit for June 7, 2014:  I received two more motors from Amazon as replacements for the broken ones, and only one worked out of the box of this batch.  I disassembled the second one and found that the motor had never been screwed to its base.  I attached the motor, and it works, but with out enough power to rotate the glass art I was hooking it up to.  These are light weight motors and probably won't work for you.  Steer clear of this product.  Half star rating?
4053103
The first one ordered arrived damaged,  seller replaced at no charge.  The second one installed in minutes and works great.  I recommend this one over the cheapest one found on amazon,  I tried that one first and it was cheaply made and the motor did not operate.
1676089
Motor appeared to burn up and quit in second brief use.  Strong electrical burning smell and motor noise.  Is it possible to obtain replacement after Amazon return date exceeded?
4549141
Though fan is very powerful, the motor broke away from the body after the first day of use. Will have to exchange.
4381180
I got 3 flights out of it and then a motor wouldn't work. I had to return. Otherwise... as advertised!
4805123
One of the four motors as bad.  No way to return just one and I'm not going to remove the other three i replaced. FYI
3270981
Worked for about 1/2 day then the gears in the motor started to break.  A couple of teeth of the gears broke causing the car to not work properly.  They need to get that fixed.  Works well when it works but some of the cheaper plastic gears loose their teeth and you are hosed.  Not sure if the teeth break from the high speed nut they didn't seem to last from our experience.  Maybe I got a lemon?!?!
1643273
I bought this because it looks like the stampede. What i got was a piece of crap that broke on the second day
2811507
It was what they said it was , but two days later I had to get new batteries