Would you swap a Sunrace freewheel hub with a Shimano cassette hub?

I'm currently fixing up my bike, and I've come to a dilemma. For background, I got a bike at a police auction, but the rims were damaged and had a bulge in both. It's a V-brake system, so it affected braking.

I got a donor bike with better rims, but it used a Sunrace freewheel. Is there a meaningful difference between the Shimano and the Sunrace, other than how the gears attach? Would you recommend going through the effort to swap the hubs?