Did my first CCR course on a rental unit with a BOV. It was HEAVY. When scootering (after course of course, but still with a rental unit) it was still heavy.
Then I bought my own CCR with a DSV, wow, that was much better. Even some others here who bought a unit (AP Inspiration) with a BOV changed them to a DSV.

On my Sidekick/Kisskat I also have a DSV (Golom Gear).

I prefer a DSV and no BOV.