I've had both strung on the same bass (not at the same time of course)... and I prefer the Chromes all the way.
Initially I had Chromes on fretted and D'Addario Half Rounds on fretless for about a half year. Then I switched them over, being now the Chromes have stayed on that same (fretless) bass for more than a year, and the Half Rounds had already been taken off the (fretted) bass and replaced by Pressure Wounds, which turn out to be the definite goal that I have been searching, round wounds that feel smooth close to flat wounds.
The Half Rounds aren't as smooth as Chromes. They both had sticky period but the Chromes got smooth faster and stay smooth up to now, while the HR stickiness had never really gone. My HR low B was dead faster than the others, no ring / overtones, no sustain, while the Chromes low B still retains its sustain up to now.