Assuming that the microphone capsules are the same, and given that there are less channels accessible with VHF over UHF, what would you say are the other advantages of your UHF series over your SC series? Especially considering that they are both using diversity recievers? Is there better frequency response on with the UHF? Is the compander circuitry superior?
All things being equal, there is no audio difference between a UHF wireless and a VHF wireless.
However, the UHF series is more expensive than the SC series. The UHF series will be quieter (less hiss); will have a longer battery life due to the use of AA batteries; and features an improved compander design.
In summary, the UHF Series will sound better than the SC. How much better? Only your ears can judge.