@riskymilk No, there are not really any other options with a lot of availability aside from the Sovtek that ship with the unit. Electro Harmonix also makes one, but that too is hard to find and not as good as the Reflektor.
Keep in mind that it is very quiet considering it is a tube unit. I believe with great tubes the unit is at ~75-85db SNR. But it is still not as quiet as some of the ultra-high end SS stages which approach 100db SNR. That said, most people are not as anal since record groove noise is about 70db SNR.