In an ideal world, it would be best to demo a reg before buying it. This experience should give you an idea of how it breathes, how heavy it feels, how easy it is to adjust, how well it purges, whether the exhaust bubbles are annoying, whether you get dry mouth using it, etc. In order to get a fair impression of the reg, the reg
must be properly tuned. You should know that the
quality of reg tuning will probably have a more significant impact on subjective breathing performance than brand.
It sounds like you've already confirmed that the Z2x has all the features you want. Atomic makes quality regs which are highly regarded by the folks here on SB. That's probably good enough.
Get the best price and order it!