My Father grew tomato's all his life in ordinary garden soil, he would mix in some of the Compost from the midden mainly horse manure and straw rotted down well. I have also grown tomato's all my life using bought compost mixed with my own compost and never equalled the harvest Dad used to get.
My best results are with bottomless pots on a gravel bed which I keep damp at all times, tomato's send down tap roots into the gravel and the damp air rising from the gravel during the heat of day appears to help. I never mixed grit of any kind in the potting mix but do start by half filling the pots then topping up with more compost every couple of weeks once the first fruit is set, it works for me.
Sorry, I didn't know Perlite was natural, it was this stuff made from tiny polysyrene balls I wanted to avoid. The only problem when using Perlite previously in the greenhouse floor was that when the watering puddled it tended to collect on the top.
Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. It is however a non-renewable resource.
Thanks everyone for your helpful comments.