I haven't had much experience with modeling in narrow gauge, but I now have six engines, and here's what I think of them
Erie #50 diesel(I got lucky, only 25 made!) Runs great, very slow. A little noisy, and the guy who custom painted it got gunk in the drivers, but I cleaned them, and it runs well
2 Westside C-16's. One has the original motor, and the other a can motor. Both run just fine. Real quiet
1 Westside T-12 Original motor, and runs good and quiet
1 PFM K-27 Heavily modified, and from what I know, most PFM's have been. A real gem now.
1 Sunset K-27. Great runner, only there was no weight in it. But it has one now.
Don't be discouraged by the posts about bad engines. Yeah there are some that aren't worth the money you pay for them, but others are well worth the bucks.