And finally, Dibond. Truly the top of substrate options. Dibond is a brand name and there are copies on the market, such as Alupanel. It is basically an Aluminium composite - so two thin sheets of Aluminium sandwiched around a Polyethylene core.
It is exceedingly strong. Totally rigid, yet not too heavy. It is resistant to rusting and in different formats, is the base of most of the external signage you see around the UK. At £40 for an A4 sheet, you can see that it is almost twice the cost of rigid plastic boarding.
Dibond comes in a wide range of colours. One side is always matt, the other side always gloss.
Like other substrates, it does have disadvantages. It does scratch, but not that easily. And the determined could bend it. Also, if you like the coloured variety, these can change in shade from brand to brand and over time as they are updated and discontinued.
It needs specialist cutting equipment, but it can be cut to any size or profile - but this comes at a price.
It can be covered in vinyl, or have lettering applied to it. If you happen to find a piece of this in a skip or on your new shop or office, don't throw it away as it can often be stripped and used again. Save money, time and landfill.