Your garage floor appears to be in excellent condition so there would be very little prep involved with epoxy.
I did epoxy on mine and I do like the sprinkles. Yes, it can be difficult to find a small screw if dropped but not too bad. My friend & neighbor did his without the sprinkles and I like it just as much as mine as it is a super clean appearance. I noticed that Jay Leno's garage is epoxy without sprinkles.
For your question on epoxy vs poly - it's generally both. Epoxy first and then a top coat of poly.
For my garage, I used commercial grade epoxy which is much thicker than the Rustoleum stuff at Home Depo. I believe mine is 23mil compared to the 3-6mil for Rustoleum. I guess it is a matter of how thick you put it on but for my stuff, it would be very difficult to put on thin as it was like rolling honey.
I also have a friend that has the snap together panels that sits on top of the concrete. He has a fantastic garage and I really like the flooring and you can do a whole variety of patterns.
Here's mine:
