11R and Apollo / Apogee

Currently am running PT 10 with the 11 Rack as my only interface. After performing an exhaustive study of the old AD/DA conversion discussion, I was wondering if anyone has had experience upgrading to a higher end interface like the Apollo Quad or Apogee Quartet to avoid the use of the 11R as your main interface. I am not concerned so much about the increase in the quality of the mic pres which I know will be a real improvement. My main question is, would paying up for an Apollo or Apogee (for starters) allow the mic, amp and cab simulations in the 11Rack to shine through more than my current setup. In other words, does using the 11R as my sole interface, and thus using the 11R converters, hinder me in any way from getting the full potential out of the 11R rigs?
The whole conversion thing is confusing but I really need to know if I am handicapping myself and my guitar tones.