I guess the question could also be worded "Would or Is playing style a key differentiator between the best engines of today?"
The CM8K/9K/10K emulations of "Kasparov" and "Anand" are cute but mostly irrelevant from a training perspective : You're essentially tweaking / customizing a plethora of engine options (drawing bias, material greed, positional tendencies as you have mentioned etc.) and mapping certain custom combinations of those knobs and dials to the behaviors of famous players ( assuming ChessMaster is even remotely accurate! :) )
I think style is irrelevant for an engine in terms of peak performance. I highly doubt Engine A beats Engine B because of style ... it's more a matter of which of them evaluated positions better and had more efficient and accurate algorithms.
I do know that certain engines are less optimistic and "harder to please" about their usual evaluations of positions (Rybka3 vs Fritz11 for example) than others.
Edit: I am also aware that some engines are programmed to be more averse to risk than the others. Could this be interpreted as style?
As you may know, strong chess playing computers don't have a true, long-term strategy, only impeccable tactics (maybe long-term tactics at maximum). It's been known for sure that computers do not do well in locked pawn positions due to the opportunity for the human opponent to create a long-term strategy. So, therefore, computers don't really have a playing style (except for tendencies to play certain pre-programmed openings more often).
Here's the question: Do you think chess programs in the future can have an actual style, I know that Chessmaster 8000, Chessmaster 9000, and Chess Master 10th edition (all strong chess playing programs), have minor positional tendencies as the computers are p
rogrammed to try to imitate famous chess masters, such as Kasparov! I am also aware that some engines are programmed to be more averse to risk than the others. Could this be interpreted as style