Apologies lads, been confined to the sick bed so didn't see the replies till now.
Cheers Rich, a OO gauge SD70 would be quite something! The Mehano one is nice in places and has some of the details the Bachmann ones does not like sandpipes and the bogies springs, but the Bachmann excels in other areas like moulded cabling on the underframe. The front and side fly window on the Mehano are oddly shaped too whereas the Bachmann ones gets them spot on. So it would be Bachmann for me.
I would go for it, they're lovely locos and Model Junction test and check each loco they send out so you shouldn't get a dud. I put in the tension lock myself as I wanted to see how she ran with a bit of a load. She'll be getting Kadees and running behind some CN locos in a 'being delivered to the docks for export' scenario as part of a CN freight hopefully. Just need to see how well she runs with my CN locos and if it's easy to consist her.