For what it's worth, Scott and the other Outlaws only occasionally post here in the saloon, so his lack of comment in this thread may not necessarily say anything either way about the design of the 990's tuner.

Since the 990 is built on an existing platform (the Sherwood 965), it's likely that they ended up using what was there with minimal (if any) changes to the tuner from the 965. The original selection of that tuner was most likely not one of the higher priorities in the 965 development process. I've used my 990's tuner too little to say much about it, although I've not found it to be any worse (or appreciably better) than the tuner from my Model 950...