I think this map is very emblematic of that older style of gameplay you'd come to expect from about 2009-2011 maps to have. There's a lot of really small rooms, corridors, indoor areas a plenty; It really wears on a player after a round or two. I also felt like there was a distinct lack of fights that happened around the map, as Whitewash is a very 'wide' map that has a lot of interconnecting routes through the map.
One thing I will give praise for is the map's visual style; This map has that sort of flair that I feel a lot of hydroelectric maps lack. A big thing in particular would be the glossy, reflective floor of RED's spawn at last. That stuff is BEAUTIFUL!
Overall, I will give this map a 5/10. I don't think the gameplay is really suited for modern TF2 gameplay or really even the playstyles of today; However, I feel like a lot of veteran TF2 players will appreciate this map a bit more for how it brings them back to home.