That said, salary ranges and transparency can create two obvious issues.
1. Negotiations - I can tell you from vast past experience that when you tell an applicant "the salary range for this position is 80-100K", in almost every case any offer below 100K is considered a slight regardless of the experience of the candidate. "...but I thought you said the position paid 100K?" is a common thing to hear. Candidates hear the top of the range, and apply/interview with that expectation.
This is only an issue when a candidate's true market rate is at the bottom of a range. A minimally qualified candidate doesn't typically see himself/herself as 'minimally qualified'. So even if 80K is true fair market rate for this candidate, and 80K is offered, the offer still has a good chance of being rejected simply because of the emotional attachment to the higher number and the feeling of "leaving money on the table".
2. Internal employees - Stack Overflow said this has been available internally for a bit, but when employees find out what others are making they are inclined to compare their own efforts/abilities vs others. It can lead to people either asking for raises to match their co-workers, or perhaps feeling slighted and seeking other employers.
Being that it's not easy to truly measure productivity in most environments - other than perhaps consulting (billable hours) this is likely to cause issues. The next step is being prepared for how to handle those issues when they arise.