An alignment table is at the heart of the way I build frames. It also serves as a base for the design/spotting fixture I have laser cut and etched to my specifications. Since it is a tool in constant use it isn’t something I would want to compromise on. The choice of table material would partly depend on how permanent the location is of your shop. A 3’ X 4’ granite or cast iron table (the best choice) can weigh a ton (figuratively and almost literally) making it difficult to ship or move again.

There are several amateur options. One is to build a substructure/base out of whatever and pour a special epoxy top that hardens flat. Another is to use a scrap of granite counter top. One of the alignment tables in my shop is cast aluminum by the Wolverine Bronze Company. It’s advantage is it comparatively light weight (under 200 lbs) so it can be reasonably mobil if necessary. The disadvantage is its $1500 price.

I prefer a bigger table than the one in your link. While it is possible to align a front triangle on a 2’ X 3’ table, a bigger one is more desirable so the rear triangle can be checked on the table as well.