I did not know that both models were in the same price band.
Can't say about the JBLs. I had auditioned the Tsi 500, versus Kef and the Rti series. the TSi500 was annoyingly veiled; seemed to have big humps in the upper bass region and overall a complete disappointment against my personal requirement.
I guess they would make good party speakers though, but i would (And did) spend my money elsewhere!
Basically I am thinking of using the Polk as speakers for an active crossovers with 6 channel amps. I am planning to rip out the passive crossovers in the speaker. I have been thinking of retaining the high pass filter for the tweeter so that I can get by with a 4 channel amp.