I think it's a matter of personal preference. I only had them on for about a day and went back to stock bushes. For me, it made the ride significantly stiffer over bumps which I didn't like. Every time I changed lanes on the motorway I felt it in my bones. Better handling can be achieved in other ways and without compromising the ride quality. For instance, fitting a set of APEX springs (just fronts) which I found them to be an exceptionally good match for the sport shockers and made the car a lot more stable and yet somehow smoother (surprisingly!) over bumps vs. oem. To retain that feeling, I would happily replace oem bushes every 6 months if I have to. The only bushes I would upgrade are anti-roll bar ones which I don't think they have too much of an influence on ride quality, but they will keep the car a tad more level on cornering.
Just for reference, I have a 318ci with sport suspension and pretty much all front components are new or well within wearing limits.