Well the Dark Magic 2 is an amazing yoyo. I have played a few and they are great yoyos. Also they come with a slim bearing as well as a standard C-size bearing. They are really stable, durable, made in America. What else could you want?
The Northstar is in my opinion, the best plastic yoyo that YYF will ever make. I have one next to me right now. I use it everyday. They are infamous for having some vibe occasionally but even when the do they perform great. They come with center-track bearings, which is a nice upgrade compared to other yoyos. Also consider, Jensen Kimmitt won the WYYC in 2010 with it.
Both of these yoyos have a great track record. I would use either to compete, because they perform on par with my aluminums. Either of these mentioned above are great. The YYF protostar is the exact shape of a Moethatar, but has a different design in the cup and is a little light. The Starlite is all plastic but basically a protostar. It also glows in the dark.
On th chaser I cannot comment, as I’ve never played one.