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).
Why not just repack the valve stem? It's cheaper, easier, and faster.
PS: I am sure the sharkbite valve would be fine.
Best Answer
This appears to be the plumbing for your water heater - as such, while there are shutoff valves for the cold into the heater and the hot out of the heater, the cold running to your various fixtures (and to here - the main water shutoff) is almost certainly somewhere else.
The water shutoff valves here are the red and blue metal handles that are shaped somewhat like:
Turn them 90 dgrees so the handles are out of line with the pipes they are on, not in line with them to shut off - reverse to turn on.
Check your water heater manual to see if you need to shut it down before turning the water off. That's pretty common.
The other red and blue handles near them appear to be for some sort of flushing procedure with the capped ports near them.