Personally the Katana would be better. Most Extras will do 3D but do not have the massive control surfaces that are rquired unless you get into the really higher dollar planes. There are a few exceptions but the Extra is generally a very good precision aerobatic plane

Now the Katana on the other hand has the big surfaces.

I haave a H9 Funtana 90 that is a direct copy of the Katana I started mine with an OS91 then an OS120 pumped then went to a YS110. The YS110 makes this thing a 3D monster.

It's whole function in life is to do 3D well and it does it well, very well. Properly power a Katana will do the same as will an extra but not as well

These are my beliefs and I could be wrong but I own both a 1/4 Extra, and the Funtana and both 3D but the Funtana beats the Extra hands down