For XB, I started with TI's then later upgraded to SXB, Super Extended BASIC. The more advanced editing options really help with programming. When editing a long line, you can jump the cursor up or down a row, or to the beginning or end. The RENUM is more flexible where portions of code can be moved elsewhere without disturbing the rest of the program. There's other features as well.
Other flavors of XB no doubt have similar improvements. RXB is very full-featured beyond SXB, but I'm not sure about its availability on a cart or if it can be ported to one for use on the iron.
Speed of execution depends a bit on the programming techniques. Short E/A routines can be developed to perform some things much faster but remain in the XB environment. For raw speed outside of writing it all in assembly, Harry's compiler is the way to go.