I finished testing my silicone chessboard, and here is my report.
I bought the board from Amazon, and it is the one listed as "WE Games Silicone Tournament Chess Mat", sold by Family Board Games and fulfilled by Amazon. It cost $15.
The board is very flexible and thin (approximate 1-mm thick). It has the heft and flexibility of a heavy fabric, but it does not wrinkle or crease.
It does lie perfectly flat when unrolled. When it was shipped, it was rolled up and folded in half length-wise, but despite the fold it still laid perfectly flat. I think it would have to suffer extreme abuse for it to lose this characteristic.
I tested the surface for resistance to common stains. I tested wine, coffee, fountain-pen ink, tomato sauce, mustard, and ballpoint. All cleaned up perfectly using a paper towel dampened with water. I did, however, clean the surface immediately; I didn't let the stains set. The ballpoint did require a little extra rubbing, but that was it.
The surface does attract lint and dust, but not in a major way. (To me, the propensity of a silicone board to attract dust has been somewhat overstated. I expected the worst and it did not happen.) To clean the surface I just used the electronic wipe that I use for my computer screen and keyboard. It worked great. If you take this board to a tournament, you might carry some of these wipes with you.
The ink or dye with which the board is printed seems fairly stable. When I rubbed the green squares with pressure using a damp paper towel, a very very little bit of the dye did transfer to the towel. This did not happen with the electronic wipe or with light cleaning using a towel. Light cleaning is really all you need to remove dust.
Pieces essentially will not slide on this board. I tried many different kinds of pieces, and none would slide. Not even those with heavy felt bottoms. So if you are an inveterate piece slider this kind of board will not work for you. You can lift pieces easily though. They do NOT tend to stick.
In general, I thought this was a great board. To me it is better in every way to the standard vinyl board (except for "piece sliding" as mentioned above.) I thought it was well worth the extra cost. The fact that it can be rolled up tightly and folded is a huge feature to me.
I do like the look and feel of my mousepad board better. But the mousepad board is bulkier and not as convenient for travelling. Also it is subject to staining and the accumulation of dirt.