he doesn't sell the controller as part of the kit, its up to you to sort out the wiring and compatibility to motor
If you buy a controller from Lyen, tell him its for LR kit and the wiring color-codes and socket will be plug-and-play. If you are using 50V X 40A = 2,000W, the 12-FET with 3077's is recommended. If you get the 4110-FETs, you can use more voltage, but fewer amps (unless you get more FETs, like the 18-FET with 4110's).
Paul at EM3EV.com also is a popular supplier for LR controllers. Both of these controller suppliers are more than happy to program the controller with whatever custom settings you desire before shipping (the Xie Chang based controllers are affordable and programmable, if you want something other than the common default settings). Paul will supply a throttle with each controller for a very affordable price ($8-$12, depending on type).
As far as sorting the motor wires, there are three phase wires coming out of the motor, they can be switched around on the three phase wires coming out of the controller with no damage until it spins in the forward direction, you only need to try two combinations to find one that will work. From either supplier, the controller and throttle with shipping should be under $200, so add that to the total when comparing prices.
You can run an external shunt from ebikes.ca to access the V3 Cycle Analyst heat controls (high heat automatic roll-back of amps), or you can order a controller with a built-in CA socket to reduce wiring clutter. Most customers don't run a CA, but that can be added later if desired.
So far, nobody I know of has fried an LR motor. A replacement motor is under $100, and if you fried the LR small-block, the GNG and AFT are not even in the same power class (they would have fried even sooner), LR has a big-block kit option if you are the first to fry a small block.
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GNG
Lowest price of the listed options by far, and uses an awesome motor. If this is the only kit a builder could afford, I recommend using 36V X 25A = 900W, due to high Kv and too low of reduction (the motor can take more watts, the drive cannot). At 48V you cannot pedal with kit at top motor RPMs, and also: brackets are not as strong as LR kit, so if you use more than 36V X 25A, it flexes badly, and needs a torque strut (easily constructed, review the thread).
The belt system is weak with too small a drive pulley (tooth-skipping). Back-bending belt and high tooth-loading leads to short belt life. The chain primary is loud, but I recommend it for durability. If you are seriously considering the AFT, then primary reduction noise is an acceptable option for you, so get the GNG chain-primary or no GNG.
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AFT
The only drawbacks are noisy primary reduction, and high price. It has a simpler install compared to the LR, and the reduction steel gears can take a ton of abuse, while lasting a very long time. Use the highest recommended voltage specified from the seller, and keep an eye on the amps and heat. Definitely get the heat-fins for the motor, they make a huge difference (as posted by AFT owners). This kit is an easy install and performs well.
The Headline motor is well-known. If you overheat it, get and external controller for the replacement motor, easily adapted onto the three phase wires. https://endless-sphere.com/forums/viewtopic.php?f=16&t=62589
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LR
The original design had no primary belt or secondary chain tensioners, to make the drive simple and efficient. As a result, both the top half and bottom half had to be adjustable length to properly tension the belt and chain. Many customers had difficulties adjusting the bottom half, so the latest version has a solid bottom half, and a tensioner for the secondary #219 chain.
If quiet operation is a high priority, this is the quietest of the three options. It comes from the factory with two chainrings, which may not be important to half the customers, but this feature was not mentioned before in this thread.
To be honest, the biggest problem with the LR drive is that it is very popular, so it can take up to 45 days to two months to actually get one in your hands. The only problem with its design is that it really does need chain/belt covers, but Mike is swamped by ramping up production. If I had a million dollars, the LR is one of the five E-bike companies I'd invest in. Off-roaders who like lots of power and quiet operation can't get enough of these drives.
