I tend to gravitate to cheaper pens including a lot of Chinese-manufactured versions of more famous pens (clones / knockoffs), and thought it might be interesting to post some of them?
This one is one of my favorites: the Wing Sung 601. This pen comes in a variety of different plastic-body colors, which are also great - I have a burgundy version of this pen which works beautifully. The style and hooded nib are clearly an "homage" (read:clone) to the Parker 51. The history between Parker and Wing Sung is interesting and complex, and has been described in detail elsewhere with respect to Hero (which owns Wing Sung.
There is a great review of this pen at The Gentleman Stationer. The version that I have is a "Flighter" all steel body (around $25 on eBay, a bit more expensive than the plastic body version but not by too much).
The pen's big highlight is the vacumatic filling system, which works beautifully. The body of the pen acts as the reservoir allowing it to hold a ton of ink for a pen this small. I find that the pen writes very well and is tremendously reliable - never a hard start, and the construction of the pen and hooded nib have meant that there are no problems whatsoever with drying out. I've picked this pen up after a few months of no use and it writes immediately. The steel body adds a little heft, which I like, and the pen is extremely durable. The hooded nib also makes for a good "stealth FP" experience, if you're in a setting where you don't want to draw too much attention to the pen.
All in all, it's a great pickup for not a huge amount of cash, and has found it's way into heavy rotation for me.
I give this pen a hearty +1. I have owned, sold, and given away a lot of 30$USD and below pens in the last decade. The 601 and Lamy Safari (and technically a brass Kaweco Sport if that counts) are the only pens in this budget I have kept. The 601 is my off the beaten path recommendation beside the usual suspects of beginner pens. The pen's capacity in a very pleasant body is the big selling point for me. The filling system is neat, and the use of a O-ring type piston (is that the technical term?) like the one found in a piston filler over the latex used in the original 601 model is an excellent upgrade in my opinion. For people who throw around their pens, the plastic isn't the toughest thing in the world, but I think your metal version solves that problem.
The hooded nib is great for slowing dry out too!
My question to you is how the balance on the metal version, especially when posted? The plastic grip worries me a little.
The balance is great - I almost always post and have had no problems. I think that its because the pen itself has a small profile, so while the steel adds some weight, it's still not a very heavy or big pen overall.
Just looked up the ink capacity which is 1.8 mL (!) - pretty nuts in a pen of this size.
Thanks for pointing out the difference between the filling systems. I hadn't realized that the 601 uses a piston type system (some reviews online suggest that the earlier 601s used the latex sac method, but it seems like the piston will not require as much maintenance over time and hopefully improve the pen's durability). This post has some good pictures of a demonstrator version to show what that piston system looks like: