Welcome to the forum. For my two cents worth, slides are ABSOLUTELY ABSOLUTELY ABSOLUTELY worth it. Just the couple of extra feet in a room make the world of difference.
I had a class C with no slides, and two SKINNY little closets on either side of the queen bed in the back. And I discovered very quickly that if I am living in it for months at a time I need wardrobe space. The addition of a bedroom slide allows builders to add closets, even in smaller rigs.
And when I have a sewer hookup, I use my W/D all the time. It's one of those that you put dirty clothes in and take clean dry clothes out -- all in one unit. Sooo cool.