Can’t comment on Kato or Atlas AC4400’s, but the 3 Athearn BB & the 1 RTR I have are great.
They pull what I want them to, they’ve never derailed even at full throttle on 18" radius curves I used to have.
Yes, they are noisy, which is why I like them. You can hear them work.
The best locomotive YOU can buy is the one that is going to make you happy, & I’m happy with Athearn.
Indeed I did notice that the original post was concerned with AC44-9W. And because the topic was titled KATO, Athearn or Atlas, by the original poster, I figured I’d offer my general comments since everyone else did.
Regarding the RTR AC unit - I think it is still valid to compare them for the simple reason that if running qualities are important, then many Athearn RTR loco’s haven’t been considered “RTR” by modelers either. Why? Because if they run like coffee grinders, they are NOT “ready to run” in most peoples books. That alone puts them on more even par with KATO “must add handrails” loco’s. What would you rather do? Press fit in the handrails or trouble shoot and correct the coffee grinder running qualities of the Athearn chassis? I submit its easier for most people to press fit the handrails and watch that sinkly smooth operation!
Anyway, as it goes, the choice of which brand is often decided on which loco/road name etc you want. Thats why when the eternal question of which brand to buy is not so simple as who makes the best quality. It is never that simple. The answer is always, “it depends”.
Kato
Kato are the smoothest running and the most expensive to buy. Certian road names can be very difficult to locate at times. I run predominatly Athearn RTR engines and they have come a long long ways since the Blue Box era. There are quality control issues, like many brands that are produced in China, so its best to test run the engine before hand to see how they run. I have a pair of Athearn RTR ATSF GP60m’s that are darn near as quiet as a Kato drive and just as smooth, they both have DCC and Sound in them now. The first thing that needs to be done with any Athearn, dont care which series its from, is check all the wheel sets with a NMRA gauge. Thats the number 1 reason for Athearn 6 axle units derailing is wheelsets to wide in gauge or to narrow in gauge if its bouncing thru turnout frogs. For whats its worth, the Athearns pull much better on our club layout than the Katos in the Dash9/AC4400 series. Proto SD60s are by far the best pullers on the layout. Your best bet is to go to a hobby shop that has both brands and test run them, see what you like and how much you want to spend. The local shop has a nice supply of Athearn RTR engines. Cheers Mike and Michele T