I would like high quality tools when it comes to saving my life. Rust on a blade is one thing, but most cheap shears use a rivet which tends to rust first and is the most likely point of failure. If we're talking about the difference between $3 for cheap shears and $20 for something better (performance, durability, even convenience), I don't really mind.
The DGX titanium coated shears are interesting. They have only 1 review, so I wonder how rust resistant they are in practice. Does anyone have them? There's a number of titanium coated shears on Amazon, many with poor reviews. Apparently opening/closing the shears wears the blades and they rust. Similar thing happens with the black coated shears. Still it's probably better than no coating, assuming the metal under the shears is stainless. The DGX shears do look different (gold color) from the other titanium coatings.
The DGX sheath is friction fit, is that really DIR? Seems like if it snagged on anything, the shears could be lost. Probably a loop of webbing through the shears handle with some velcro could make it more secure, but I'm not exactly a whiz with a sewing machine.
I like the 3.5" shears I linked above for their size. Those seem to be the only 3.5" trauma shears available, all the others are 5.5" or 7.5", with 7.5" being the standard size (which is huge). The 3.5" still cut a penny, so it seems like they'd work fine. I'd preemptively replace the rivet with one that won't rust (as fast). The only issue is how to mount them. I'd probably have to make my own sheath, which may be possible. I'd have to solicit my mom's assistance!

---------- Post added September 14th, 2015 at 09:48 AM ----------
DGX looks like 7.5", but they don't actually specify.
The
Prestige Medical Fluoride Scissor come black coated in 5.5" and has 800+ reviews. A number of people say they resist rust well. One guy complained they rusted and posted this pic, saying both shears had the same sea water exposure:
I don't know why the black rusted so quickly for him when others say it lasts longer, but what is interesting is the rivet on the black shears did not rust while the rivet on the typical cheap stainless shears did.
The
Highland by XS Scuba Titanium EMT Shears are $20 for some reason and 7.5", but I mention them because they explicitly say they have a 304 stainless bolt instead of a rivet.
So far I like the 3.5", then the 5.5" Prestige, then the 7.5" DGX.