The IRD looks more expensive to me, but that's not to say that the Sunrace freewheel doesn't look great on the bike, it does!

I've had some Sunrace freewheels over the years with somewhat rough bearings, coincidentally these were packed with thicker-thn-normal grease from the factory.

I've also has one or two Sunrace freewheels out of 20 or so that had a "tick, tock" rocking in certain gears. I had to open them up to adjust the bearings a little tighter.

The Sunrace freewheels are an unbelievable deal for the twenty dollars or so that they go for online.

Sunrace freewheel shown on top, Giang (IRD) freewheel shown below it.