I've held one in my hands. Never thrown one though. But here's what I saw - and more importantly, what I felt.
I'm guessing "machined" must be a loose term. The edges of the reel where the spool clicked in place next to the frame were ridiculously sharp - enough to cut my finger if I slid it around the edge. I'm thinking ANY fly line would easily get shredded if during winding, the line touched those sharp sides. There were also several tiny, but very sharp "burrs" that were lifted at the edges of the reel foot. They easily scratched through the skin on my fingers.
Take the good advice of everyone that will most likely chime in and tell you: "DON'T BUY CRAP COMPONENTS." Pay the money and buy what you know is legit. I'm telling you - from someone that's made this mistake before (just to see what it was all about) save your duckets and buy the real deal. Get yourself something that has both a well-known name on it
and is truly machined - if that's the direction you're heading.
Bells and whistles on fly reels only means more things to possibly get messed up. You don't need to go all the way like I did. For my ultralights, I use nothing but Galvan 2.5 reels - the green ones. Not even sure you can find those anymore. Plus, I bought a few really nice early Orvis 123 reels and extra reel spools for them. Also got lucky and made off with the last Orvis CFO 1-D green reel and extra spool (still not sure how I pulled that one off) from my local fly shop. There are no more to be found anywhere as they are collectors items now. I have no idea why I bought the "O" reels - I refuse to take them out fishing for fear they might get scratched.