Either the CZ 75 B or the BD are fine choices for hd and competitive shooting (such as IDPA). The question here really boils down to do you feel comfortable with manually decocking a loaded pistol? The standard CZ 75B has a manual safety that will allow for cocked-n-locked carry. The safety can only be engaged when the hammer is cocked but there is no decocker. In order to drop the hammer, you'll need to hold the hammer and easy it down while pressing the trigger. You'll get comfortable with doing it after a few range trips - although it may scare your wife! My wife is still practising with snapcaps and won't attempt a decock with a loaded chamber. 
The BD is easier to operate in this respect.
I personally prefer a manual safety as it gives you more options to how to carry - either hammer down or CnL. With the BD you're stuck with just hammer down carry. I don't do any competitive shooting, however, I can imagine in IDPA, when moving between shots, having the safety on would be a safer way to travel vs decocking and then having to take another DA shot.
When I bought a CZ 75B, I was intent on buying the BD version because almost all of my autoloaders were Sig. At the time, Angus couldn't deliver a BD and since my need for gratification was at it's peak, I "settled" for the maual safety. I'm very glad I did.
Manually decocking this pistol requires concentration, but it is quite simple. The manual though, is not precisely clear. If you hold the hammer, pull and release the trigger, the hammer will lower to the same spot as the decocker would place it. If you hold the trigger, you can ride the hammer to "full rest". The first is obviously the safer and if you practice and become comfortable with this, you have, as you point out, a more flexible pistol than just the BD version.
The BD may also add a layer of complexity that some find undesireable.
