Well not sure I could give you a solid answer as I suppose it's how you work. I too use an older version of PSP to do some things because it is just natively faster than the newer versions which placed too much bloat into it.
As Giz and SD say. They are comfortable with how BC works and thus I'm sure they work faster in that then they would (at least initially) in UC. Doesn't matter if it has a bunch of bells and whistles if you don't use them.
Here is their feature list if interested, but if you're comfortable with BC and it does what you want then I too don't see a reason for you to change. But if you're a new user to this type of software then I think you would probably be better off starting with UC.
http://www.ultraedit.com/index.php?name=UC_Features.
