In the NBA, there is a direct correlation between teams who are paying over the soft-cap and teams who make the playoffs.
obviously there are some exceptions, but in general, the higher the team payroll, the better the team is.
Top 10
Lakers
Nets
Magic
Heat
76's
New York
Portland
Boston
Chicago
Clippers
Bottom 10 payroll (lowest to highest)
Rockets
Kings
Bobcats
Suns
Bucks
Memphis
New Orleans
Utah
Indiana
Toronto
some obvious exclusions to the rule, but in general, if there was a soft cap, it wouldnt make a difference - all the teams with all the cash would just aobsorb the cost/tax would just buy a team better than everyone elses.