Water – Spigot replaced with ball valve- now the water gets out like from a water cannon…why

I'm not a professional plumber (though I did work on water treatment systems for several years), but in my opinion what you did is fine.

Gate and globe (stop) valves are prone to corrosion and generally wear out over time. Ball valves are much more durable and reliable. I've seen many, many old stop valves that are leaking or don't shut off properly, or more often, leak as soon as you open/close them after they've not been touched for years. I can't say the same for ball valves - I've seen many that were installed for many years and still worked. I can even think of a couple where the outside looked totally corroded, and though it took a lot of force to turn (and sometimes a replacement handle), they still reliably shut without leaking.

On top of the reliability, the fact they use a 1/4 turn (instead of several full turns) and a quick glance tells you whether it's open or closed, ball valves are just vastly superior to gate and globe valves for almost all residential applications. Worth the extra dollar or so they cost.

The only thing they are not as good for is applications where you want to limit/control the flow rate (such as an outside tap or sample port). They can still do that, but are harder to finely adjust, and especially when one hasn't been opened for a long time and is a bit stiff, tend to suddenly give and open to full blast (I've been sprayed while trying to take water samples many times).

YES! I came across a 10:1 flow rate differential between 3/4 ball (25 GPM) and 1/2 globe (2.2 GPM) There's almost a 50% reduction, just going from 3/4 pipe to 1/2 pipe (I inferred the pipe size flow differential by comparing 1/2" and 3/4" ball valves of the same type here). Table 2 here Compares 2" ball at 228 and a globe at 44 for a ratio of 5:1, then add in pipe diameter and 10:1 seems reasonable.

Be sure they put in a full port ball valve in bronze with drain (on house side). Full port has the least flow restriction. Bronze is safe for potable water, the drain is for future repairs to drain the lines.