In the FWIW department...
I tried a RigBlaster product several years ago and was not impressed. It was very susceptible to EMI/RFI. I had to get out the copper tape and even it was not enough. But, to be totally fair, that was then and this is now. The newer RigBlaster products, like the Advantage, may be much better.
That said, you might also look at the RigExpert and MicroHam lines. I personally have a MicroHam USB III which I used with an IC-7000. It was bulletproof, provided true CW and FSK and was the cat's meow. Now retired to Emergency Backup status since I have a Flex, but it was the cat's meow.
MicroHam was the leader in this area a few years ago. The now very similar RigExpert and RigBlaster products are following in their wake. I suspect that the RigBlaster products have come a long way based on how similar they now are to MicroHam. I say give it a shot, particularly because it is much less expensive than the "leaders". I'll be very interested in your RigBlaster AAR.
Sorry, I digress...to answer your original question, it ought to be head and shoulders above the Signalink, but, again, I look forward to your AAR...