it is an excellent machine. i tend to use different polishers on different days. just to change up. been loving the 14-250 lite weight rotary. the flex products in my opinion are smoother running and a bit more powerful. the 3403 is just a little heavier though than some da's. you will not be disappointed with this tool.
I would go Dewalt over 3403. I have the PE-14 and use it all the time but its kinda expensive for a lot of people. I didn't like the feel of the 3403 nor did I like the speed setting for it. I tried the DeWalt and loved it. Great machine and built to be a workhorse.