Apart from the obvious (as is in one folds, one doesn't) is there any real difference between wire beaded tyres and their folding equivalents.

wire: heavier and cheeper to make

Kevlar: lighter and costlier to make

As a result cheep tires tend to be steel beaded. No point making your super expensive lightweight, tubless, 130tpi, triple compound super tyre, then saving £3-£4 by putting a steel bead in it. Similarly no point adding £4 to the cost of a busget tyre aimed at soemoen who doesnt need/want to save 75g.

Many wire bead tyres have fewer tpi than the folding equivalent meaning that (in theory at least) they're less flexible and therefore more draggy and less grippy.

In reality, unless you're a racer, I reckon it makes very little difference (for most brands at least).

Interesting about the grip, a lot of not so cheap DH tyres are wire beaded and they're grippy as hell.

So, in essence the wire beaded versions of XC tyres are cheaper and marginally heavier, but just a grippy?

It was a generalisation.

Most cheap steel bead tyres are heavy with a low thread count to keep cost down, in these instances they will likely be less grippy. They often forego some of the puncture protection and such too.

Some expensive tyres are still heavy, but have a much higher thread count. There's not a lot of point in making a 1200g Maxxis Minion kevlar bead and saving a couple of grams though. I imagine there's something in there about the rigidity of the carcass too.

If performance is a key factor, get kevlar, if not, get steel. With XC tyres at least.

The DH tires probably reach a point where the exta weight isn't an issue, although i'd put good money on most World Cup downhillers running kevlar tires and tubless, even if the tires arent available publicly.