I use some D1s (same design) along with Acute Bs and 1200s and Compact 600s and will be acquiring a B1 TTL-N.
The D/B1 light as is (flat glass) is nice. The slightly recessed tube vs. typical Profoto lights gives a spread of (IIRC) 70 or 77 deg, so I find with a beauty dish or large (>- 4x3') softbox, the optional dome is a good idea to get more even fill. Not the same as the 180 deg throw of a normal Profoto head, but much better than just flat. On the other hand, the flat glass front makes creating a tight throw with a grid a very compact situation - no bulky reflector needed.
While I prefer the bulb style (exposed) of my AcuteBs, etc., over the D1, the D1/B1 has it's place. The benefits of the onboard Lio battery and TTL of the B1 aside, the D1/B1 design are quick to setup, dead easy to operate and VERY tough.
I had a well meaning friend remove the counter & base weights from a stand holding a boomed D1 (with dome) BEFORE bringing the boom back in. The entire C-stand, 40" arm and D1 pivoted downward onto concrete, maybe 6' - and hit D1-dome first. I just removed what was left of the shattered dome from the D1, put the flat glass on and was using that light again the next day with zero ill effects. No damage to the plastics or internals.
I do a lot of work with animals and when shooting outside often can't meter as would change the scene and having the ability to quickly and easily move a key light w/no cord, pack, etc., has it's merits in some situations - hence why adding a B1 TTL-N. For a wedding shooter, the B1 would be a real treat.