Let's put it this way: MIT makes a good neutral (ie accurate) cable with good (ie low) time smear properties. But that only applies to their upper models, not the ones you are using -- which are about the same as most mid-priced product from any of the major manufacturers. If you like the naturally warm tube sound but not overdone, the expensive MIRs would be an OK choice. For the same money as the upper model MITs though, you should consider either Purist or Transparent as having better performance in those same with quieter background -- especially the Purist products.
What your dealer said about MITs not being appropriate for a tube system is highly suspect, but might in fact apply to an acknowledged warm and fuzzy cable like Cardas.
Bottom line: Don't simply change your present cables for a similar mid-line model in another brand. That would be a waste of money. And if you're going to move up, consider the two other brands I mentioned, along with Straightwire, Madrigal, and Synergistic.
What your dealer said about MITs not being appropriate for a tube system is highly suspect, but might in fact apply to an acknowledged warm and fuzzy cable like Cardas.
Bottom line: Don't simply change your present cables for a similar mid-line model in another brand. That would be a waste of money. And if you're going to move up, consider the two other brands I mentioned, along with Straightwire, Madrigal, and Synergistic.