I'll keep brands out of the discussion, just to keep any bias out of an answer
My current unit has 2400 W P-to-P power, 300 W RMS with

128 x 64 resolution.
I'm looking at a new one with 4000 W, 500 RMS and 640 x 320 resolution.
Just how much detail am I going to see with a new unit, if I go with that one? It's a pricey investment to me and I don't want to be disappointed.
Is it just the resolution that will make the biggest difference, or is paying for the power really worth it?
Thanks for any help you can provide.