So I recently purchased a ViTrains V2088 Class 37 No.37416 in Royal Scotsman livery and a Bachmann 32-780V Class 37 No.37248 Loch Arkaig in a West Coast Railways livery, a Model Rail limited edition. Both have their good points and bad points.
The Bachmann loco is heavier and more well detailed, but it appears to be a bit narrower than the ViTrains loco. Also the ViTrains cab windows look to be more the correct size to me. The Bachmann loco is also a few mm longer than the ViTrains one, as well as having cab interiors and a driver in place. The Bachmann loco is 21 Pin, whereas the ViTrains is only 8 Pin. The colours on both look good to me, except for the yellow on the ViTrains. It looks more Fluoro shade than Bachmanns. I do like that the snowploughs on the ViTrains are 3 seperate pieces so you can fit just a centre, or just outside, or all 3 as wanted. Ive fitted the 2 outside ones on the rear of the loco with the coupling in between. And Ive cut and glued the Bachmann one onto the coupler too.
I'll let the pictures do more talking.