They basically do the same job but it's a different approach.
Using the preset approach the bottle can be unscrewed and like i do, used to power two guns, but the maxflo style reg is bolted to one gun and cannot be easily switched. If you only have one gun then the maxflo is fine but if like me your tight and only have one bottle for two guns then you'll need a preset.
Hope that helps
Colin
Ps, i see your in maidstone, who are you playing for?
Rochester lad myself.
Later