I have BC racing BR series coilovers and love the ride:
I have the back raised a bit, and the dampening settings set to 10/30 for a soft ride. So if 3 full size adults sit in the back with a loaded trunk, the car is quite balanced lol, and I don't bottom out. Parents and family sit in my car, so its essential for a good ride quality.
I sat in an i35 with Eibachs and illuminas and wasn't impressed. Too stiff. This is above all, a luxury car. I have yet to try H&R's, I hear they were less stiff, but I hate the rear sag with any spring strut combo. Coilovers let you decide the balance.
For the money you will spend on a spring strut combo, you are better off spending a bit more and getting coilovers..
Good luck with the decision.