I never tried the Rertrospec, but would love to some day, I have a small collection of DIs and do a fair amount of playing on other peoples recordings where I'm always pulling something else out and done a fair share of A/B-ing...In a decent mix I can hear it the difference.
To be fair, both the missing link and the retrospec are transformerless. You are certainly going to hear a difference between those and a Jensen transformer based DI. But, I consider the transformer to be a flavor. A great flavor, just perhaps not always an appropriate one. Of course, if you are only going to be using one DI, a Jensen may be the way to go if that is what works for you.