The AS Deltic promises a LOT more than the Bachmann - no doubt.
We've seen a video of it in operation - early prototype, and it looks superb.
Thing is, it's still an unknown entity.
The Bachmann is known, functions well, 'does the job', and isn't half bad.
Assuming the AS 55 does the job as well as anticipated, it does make the Bachmann look a bit on the expensive side ... even if it were the same price.
I have one on order, so I'm expecting the same as everyone else.
Al.