My 'L' motors always run HOT because the windings are thinner wire, so you have to watch out you don't fry them as i did one of mine at a very wet meetings where i wragged a 5.5L to the point I burnt it out
very good motors but be sure to gear them right and treat them nicely espec in 4wd, the 5.5L in my 2wd was freakin awsome to point i sold it when i changed motor brand
bonded rotors are pretty much obselete now and no-one tends to produce them now as sintered is so much better in many ways, I don't run a heatsink or fan on my motors as they don't need them and most offroad cars don't have the space for a decent heatsink or fans in the chassis to help keep the motor running cooler, I just make sure my shells are well ventilated at the front and rear the hot air inside the car can escape so the fresh air can help the motor run alittle cooler, slots in the can of the motor in some brands are just there to run a little cooler although i don't think they make a huge difference but can then let dirt into the motor which some may not like, there are alot of brands now that are all very reliable like lrp/nosram, novak, speed passion, losi, tekin etc i could go on... sensored i think is better as you have more control over the throttle than with sensorless thats more like an on off switch. I don't have a 'worst motor' as all the brushless motors i've tried that are sensored have all been very good and not much different from each other, I guess it's more of a which brand and colour do you want these days as there isn't any real advantage from any of the top brands in my opinion