I guess each region is different. Most of the boats I see on the lake I fish and at the marina when I keep my boat all have fish finders on them. You can find some very good fish finders without the high price tag in the smaller sized screens. That is what I bought for years.
I have sunk a lot of brush piles over the years but lately have been using the porcupine fish attractors as they are easier for me to construct and handle. I don't mind other people fishing "my" spots as I will just go to another location if the one I was going to fish is occupied. On another board I gave a list of coordinates of brush piles that I have to anybody who asked for a copy. I will continue to do so as it has not hurt my fishing one bit. I also don't mind other people fishing my brushed out slip if I'm not fishing it. Crappie move and those that are caught today will be replaced by other crappie tomorrow if the structure is good.
When I first started crappie fishing I was given a lot of help by other crappie fishermen. So I have always felt it was only right to pass that help along to those that need it. If telling somebody a good location to fish helps them get started then that is what I should do to pay back the help I received.
And SK's advice of fishing the smaller brush piles and structure is good as most will pass them by even when they know about them.
And I still like the large H shaped markers in bright orange as I can see them better.