I play 50+ league here in R.I. and we use a board instead of a mat, made from 1/2" plywood and painted white with the outline of home plate on it. I've played in quite a few tournaments now and some use a mat, some a board. I'm curious if anyone else has a preference, I know I do.
I prefer a board for multiple reasons, first and foremost there is never a doubt if the ball hit it or not due to the sound. In 2015 when I played in the WMC I was at bat and the first pitch clearly hit the mat but the ump called it a ball(thanks). This would not have happened with a board. I've also seen a lot of iffy pitches on the edges that were called the wrong way, IMHO. Again, with a board this doesn't happen. When a pitch hits the edge of the board you know it.
Secondly, the mats are usually black and for me, with my old eyes, not always that easy to see. The board, painted white stands out and is a much easier target.

I think if SSUSA mandated use of a board it would make the umpires job easier and would also help out us pitchers with our old eyes, opinions?

Differently the board. I pitch to the edges of the mat and one year we went to a rubber mat because of the ricochets off the wooden bat slowed up the game. All the good pitchers complained that we were loses strikes on the edges so we went back to the wooden mat.
The black mat I agree. Most of time I had a hard time seeing the edges. All mats should be white with a black painted silhouette of the regular plate. Now that gives me a perfect target to shoot for.

Several of our sanctioned leagues use the board vs. the mat, and we're fine with that ... But it's unlikely we'll switch to the board for SSUSA administered events any time soon ... It would be expensive, cumbersome and generally really difficult to ship a lumberyard around the country all year! ...

As a pitcher, I prefer the board for all the reasons mentioned above. We went to a board in our league some years ago. There were a lot of concerns that the right handed batter would trip on the board when starting to first. Never happened even once. Now we alternate mat and board. Some think the board is not as stable when the catcher is reaching out for a low throw.

As a batter, I'll take the mat!

If SSUSA allowed a board plate, wouldn't the local tournament locations have to provide the board like they do now with the rubber mat?

Thanks Dave. Just curious, does SSUSA supply the mats or is it the parks that supply them as DieselDan suggested?

Another thought, if boards are out of the question what about using white mats?

PoolShark and D-Dan ... It's a mixed bag ... For the SSUSA sanctioned and administered annual events, like the TOC Qualifiers, the East/West Nationals, the TOC itself and the World Masters, we typically supply the mats initially and leave them at the facilities ... From year to year, as the events get closer, we confirm that the site still has them (not all do!) and doesn't need replacements ... If they need more, we order from a local Sacramento rubber fabricating plant that manufactures and ships them or, if time is tight and someone from Sacramento is driving, we bring them that way ... With independent Tournament Director events, we generally refer them to our fabricating company if they wish, or allow them to get their own locally, with the proper dimensions ...

We are not against the use of wooden strike mats, but rather to use rubber for our administered events ... As for colors, black is a really easy to get color (since these are made from standard truck mud-flap stock) ... Again, we don't have any objection for those who want to go with a different composition or stock, so long as it's 34½" by 19", isn't too thick to pose a tripping hazard and will stay reasonably in place during play ... We're not likely to mandate a change in composition or color because doing so would require the independent T.D.s to incur the unnecessary, in our view, cost of switching them out ...

Dave ... The cost of the tournaments entry fee with all the tournaments the SSUSA holds over the course of the year should more than cover cover the costs of new mats if they were to choose to change them ....... just a side note from my experiences so far with SSUSA they are set in there ways and really don't want to make any changes that could possibly speed up the game or make it any better for the teams and people who play this game that we Love.....

A "board" plate would have to be treated to help prevent warping do to rain, condensation, and infield watering.