I have both the 4-1/2" and 5" Makitas. Note that my 4-1/2" doesn't allow the blade guard to be repositioned. I have found this to be a bit of a disadvantage if you're left handed. There may be another 4-1/2" model.
I would also recommend buying a spare set of brushes if you plan to use it a lot. They are inexpensive and easy to replace, but don't give you a lot of warning when they wear out.