Nancy, I basically agree with Tom here. If he used particle board, it would be ideal if he'd used industrial hi-d particle board. I'm not a particle board fan, but the hi-d is fine for laminate tops; comes 49" wide instead of 48", so you can get 2 lengths of top from one sheet, and it's a much tighter-made material that withstands water far better than regular particle board.
The washboard effect, to me, sounds like his glue was not applied evenly, and he didn't get good adhesion; this might especially be true if he used water base laminate adhesive. It's good stuff, but can dry unevenly and if the top is applied while some is still damp, it will never adhere. Try lightly tapping your fingernails along the length of the top; you'll be able to hear a distinctive difference between tight and loose areas.
As to the tile, it's hard to say; some tile are purposely very irregular, as part of their characteristics, and won't always be flat to the surrounding tiles. If the tile is a smooth and regular tile, and was adhered with mastic, they should have aligned quite easily. If the tile was installed with a mortar, it's easier to get tiles out of plane with each other. If by "not flush" you meant crooked or misaligned as they follow the countertop, that's certainly a poor installation factor, again unless these are purposely irregular edged tiles.