My favorite double star scope is a refractor, but since I cannot handle a large refractor any more I also have good success with my 6-inch f/12 Mak (sub-30% CO).
I am a double star guy and I have had fun with every scope design I owned. My first split of Sirius was about ten years ago when it was tighter - and I had an 8-inch SCT at the time. The optical quality wasn't so hot, but the scope was sharp enough to give me a clean split.
My favorite eyepieces have been my Leica and Baader Zooms with the appropriate Barlows to match the focal length of the scope. The zoom allows me to "push in" to the maximum magnification the atmosphere allows on any given night. And I still use and enjoy Tele Vue, Pentax, and Baader fixed focal length eyepieces.
The main key to success IMHO is a solid mount. This will allow you to push the magnification up to the maximum allowable for the conditions no matter what scope and eyepiece you are using.