Personally i chose the Profi couplers after recommendations from friends as they are very reliable, something i have been told that the Roco couplers are not. I haven't actually tried the Roco 40270 couplers yet, i think, but i do have a whole bunch of them at home from cars i've changed couplers on. I might give that a try.
But for russian cargo trains (you know, cargo rolling stock in Russia have not buffers) I think the best choice is a Kadee couplers. It can be installed into NEM pocket, it looks like SA-3 and it is working
I am aware of that, but i have always wondered why it's like that. In the US, Canada, and Mexico they also have "knuckle" style couplers, but no buffers on any rolling stock.
Anyway, i do have a few Kadee couplers at home as well. But when it comes to freight trains, which i don't have any yet, i was thinking of atleast trying to use the Roco SA3 couplers. They may be meant to be decorative, but you can couple them together. But if that doesn't work, well, then it's Kadee. That much i know.
On the locomotives - Kadee. And on the first passanger car from locomotive side - Kadee to couple with loco. Usually it is #18.
No problems with the buffers there?
I use Roco "Goldorak" Universal 40395
for all my waggons and cars because of its compatibilty with old style coupers (for exemple Roco 40243). I think they are more durable in case of frequent coupling/decoupling of the rolling stock.
Ok. I've never tried those, but i did get two similar ones when i bought my only Märklin locomotive. Might give them a try.
Kadee (IMHO) are not suitable at all if the rollig stock that have buffers and a short coupling mechanisms. But they are really excellent for rolling stock without buffers, i. e. russian or, for exemple, american.
There's one other member in the model train club i'm in who runs Russian trains, and he has actually removed the buffers from his passenger cars in order to use Kadee couplers, normally using one long and one short between each two cars.
I don't always post in Russian, but when i do, i use Google Translate.