I would want to see this to believe it. I have a 300 and the visiblity in sunlight is bad. You have to have it a just the right angle to make it tolerable. The backlight (which is what you get with DC power) makes it tolerable at something other than 'the right angle". Tolerable in the perfect circumstances is far short of good.
So I would say, go find one, take it outisde (drag the sales staff with you if you have too) and see how it compares to a 60C. If it's as good as the 60 they have greatly improved the screen. If you can see it with the backlight off but not quite as good as the 60, but you don't have to shift it to the 'perfect angle' that's also an improvment.
I went from a 60csx that I still have to a new 450. Do what I did and buy from EMS or REI so that you can return it if it doesn't suit. I'm impressed with my 450. T screen is a little more difficult to see but not that bad. The paperless and field note features are outstanding. Read the Wiki's to see how to set up the screens. Download a white background and use it instead of the fancy ones that are in the unit. It makes a difference.