Adjustable gas blocks

[BoringGuy45]

What are some opinions on having a Switchblock or something like it for if/when one shoots with a can? Are they enough of an improvement that they're almost essential, or are they like a piston: A solution in search of a problem?

[SWThomas]

I don't think it's required, it's that it reduces the amount of gas so the extra pressure from the can doesn't beat the crap out of your gun as much.