Are you sure? Given I have never tried the SRH840 and I used to like the V6 until I found headphones like the Monitor 10 I would not recommend a V6, only for casual listening. Also the CD900 ST was more to my liking but the CD1700 just trumps it in my opinion. The CD1700 is a very refined headphone and under-appreciated at the same time.
"Because it's a Sony"? Check Pioneer and Philips. Some brands are just popular because the marketing machine behind them is more effective yet a Philips HP1000 sounded - i.m.o. - more 'natural' than a K701 and both needed a lot of power. Pioneer once released the Monitor 10R and I directly compared it with the K701 - twice - and for some reason the AKG just sounded 'veiled'. The low end was unacceptable on the AKG. Guess which headphone sold in bigger numbers?
The Sony brand name still commands some respect given the reputation of the flagship headphones like the R10 and CD3000.