I bought the $43 Adjustable "MZS Tuning" Levers from Amazon, and I have to say I'm pretty happy with them.
Specifically, I bought the more "squared" design because I think they look better with the aggressive and hard angles of the FZ-09's styling, over the smooth and rounded levers. MZS makes both styles at about the same price. You can see how the squared design looks installed on my 2017 FZ here.
I went with these levers over the more expensive options because I wanted to try out short levers, but I didn't want to invest a lot of money in a "good set" then end up not liking shorties.
Machining quality is satisfactory. I don't really have a good basis for comparison, but I can tell you there are no imperfections, burrs, or sharp/rough edges on the levers I received. Yes, you can see some tooling/bit marks from the machining process, specifically on the flat areas, but it really doesn't affect the use of the levers at all, only the looks. I would by no means consider the tooling marks to be "rough."
When setting the lever reach/distance adjustment, the "dials" click in place firmly and I don't see them getting knocked out adjustment by accident. This was a big concern for me because I figured if there was anywhere the "cheap levers" would fall short, it would be failing to retain their reach/distance setting under normal use. This, so far, has not been a problem at all.
The finish on them seems to be of good quality. They definitely DO NOT have that cheap keychain anodized color look to them. The black and red coloring is nice and deep. Only time will tell if the colors hold up, so I currently cannot speak to the longevity of the finish.
I have been using them for about a month, and overall I have no complaints. If I really wanted to point out a negative, I'd say the hard angle design of the levers can make your fingers a bit sore after a long day of riding. However, wearing gloves alleviates this entirely so it's really not a problem at all. This should specific to the style/design of the levers I chose and has nothing to do with the quality of manufacturing.
Installation was really easy and straightforward. No, they didn't come with any instructions, but if you're concerned about that there are a few different videos on YouTube showing you how to do it. Specifically, I followed this video. The whole process took me less than 30min and I have never changed motorcycle levers on anything before. The hardest part was making sure I adjusted the clutch cable slack correctly, and that was more to do with me not having much experience than the bike/levers themselves.*
Let's be honest, these are levers, they serve a pretty simple purpose. Unless you install them incorrectly, there's not a whole lot that's going to go wrong with them.
I personally find it hard to believe that the more expensive levers function any better than these do. Style and range of adjustment may be a different story, but that comes down to personal preference.
I highly recommend the MZS levers, if you are on a budget or just wanting to try out short levers without spending too much money, you can't go wrong here. They work great and I think they look great.*