Beersmith 3 is now available and I just installed it. I threw together a recipe in Beersmith, matched it to a water profile, and then compared it to Bru'n Water. They both agreed almost perfectly on the final water composition, and while Beersmith predicted a 5.4 pH, Bru'n Water predicted 5.38. I think I can live with that.
It's nice to have all of the water salts listed in the Beersmith recipe, but there's one glaring problem for me: calcium chloride. It tends to absorb water and throw the weight off, so I do as Bru'n Water suggests and mix it up in a large bottle of distilled water. Bru'n Water allows me to choose liquid CaCl and I can enter a custom strength of the solution. Beersmith doesn't seem to have that option. Beersmith suggested that I add 1.02 grams of (hypothetically) pure/dry CaCl, while Bru'n Water says that I need 5.01 grams of my homemade solution. I'll have to continue referring to Bru'n Water for the actual measurement unless/until Beersmith allows for liquid CaCl at an adjustable strength.