It's a bit difficult to tell just how much is die back and what may just show as an off color due to the photo quality. Having said that, ALL Japanese maples experience some winter die back - usually not a big deal. It is pretty easy to detect as the dead wood is more gray than any other color and there will be no sign of bud life, which should be present now on any healthy growth.

'Bihou' is not the most robust of JM cultivars and can be prone to various bacterial pathogens that can cause excessive die back and worse. Often these manifest as black rather than gray wood, if that's any help (but not a guarantee). At any rate, since it is a new and relatively pricey selection, I'd want to make sure I was getting a healthy, quality specimen for my money! Why pay for problems?

'Bihou' is already notorious for dying back. Mine is going to be discarded when I get around to it.

Because it always gets dead tips.

Assuming climate and soils etc. are suitable there you can get the same color scheme from any of several red-and-yellow Cornus sanguinea cultivars now on the market. These glow like lamps during the winter. The 'Cardinal' dogwood can also be very appealing.

I read about Japanese maples having dead ends when needing fertilizer, put some on my 'Bihou' and now it is growing like a weed. But this was not the blackened, shriveling stems of bacterial blight, this was silvery, dry tip sections.

I was given a free Bihou by Conifer Kingdom and gave it away-- too much info out there about how easily it's infected and how often it gets dieback. I've seen some pretty ones out there, but they seem awfully picky about conditions. Much of whether they thrive seems to be luck.