The alignment of the planets has not changed just because the MoCo put a GPS thingy in a fairing. You are always going to get the sun reflecting off instruments, GPS, mirrors, chrome, watches if you wear one and the list goes on. It does not matter if you are 4 foot tall or 7 foot tall if you have the sun behind you at some point it will reflect off stuff and be a PITA. It's one of the joys of heading west later in the day.
I move my Melon (head) so I cut the sun off, I also wear glare reducing sunnies and a brim on my lid. Looking at the GPS is not my biggest worry as heading into the sun it is often difficult to see the road and/or oncoming traffic.
As far as the BOOM Audio GPS goes I would be interested to find out if anyone has tried some kind of touch screen anti-glare/reflection covering and how that goes. Wonder if it makes it harder to see at night?
Cheers Tom