I purchased a TSDZ2 48v 500W motor and a 48V 14.5Ah Frame Panasonic ebike battery pack from Auto-ebike from china direct - http://www.auto-ebike.com/
First my feedback on the purchase- it took just over 3 weeks to receive both items. They arrived in excellent condition despite poor boxing. No instructions or paperwork. The cost was $70 higher than the checkout (I was informed 3 days later and decided to comply with a request for second payment), due to their website not accurately including the cost for shipping the lithium battery- which is indeed a difficult thing related to fire safety regulations regardless of where you buy the batteries. Overall I believe I got a very good price. So far the products seem excellent.
The installation took me a while, since I haven't done much work on bikes before, and had to get some parts. I needed new handlebars to accommodate the hand controller, a new brake lever, and had to make an electrical connection between the battery and motor since they came with incompatible connectors. All no big deal.
I've done a couple rides now, including a 10 mile rough dirt road ride up a ridge that this 56 yr old body would not have attempted without the motor assist. My bike is a simple Schwinn hybrid with some thicker tires than it originally came with. My initial results are excellent. The torque sensing assist is very good, and this feature is really the only reason I purchased this unit over a Bafang. There is no other cost-effective way to get torque assist on the market, as best as I have been able to find, and I consider it to be the paramount feature of selecting a motor.
The motor is strong, smooth and quiet. The big question mark is durability. We shall see.
With about 20 miles of riding, with considerable hilliness, I have only used 1 of 5 bars of battery power! Impressive. But I do have a beefy battery.
My only issue with the design and install relates to getting the rear derailleur cable to travel under the bottom bracket. There is no longer a gap that can fit the cable guide, so I just removed it and the cable now sits right up against the bracket frame. It works just fine, as it scrapes away at the paint (and aluminum?) along the undersurface. I see no solution to this on my frame.