Better than most that I have purchased.Good storage case. Drills are good qualityQuality is very goodEven with use of cutting oil and appropriate dril speeds/ loads, these bits havent kept a sharp cutting edge.The bits seem to have a very soft shank so any slippage in the chuck will gouge the shank.I already have a complete (115 pc) set of Chicago-Latrobe 550, which are also Cobalt, 135 deg, split-point, straw-finished bits. I bought the Drill America bits as a lower-cost complement for work where I want the extra hardness, heat resistance, and sharpenability (more on this below) of Cobalt but don't want to risk breaking my good bits. The bottom line is that while the Drill America bits aren't up to the level of the 550s, they're as good as or better than expected for the price.I've used onee of these bits top drill holes in annealed O1 tool steel plate, and it held up as well as you'd expect from Cobalt HSS, though maybe a little worse than I'd expect from the C-Ls. The C-L 550s are M42 Cobalt HSS, and it would be interesting to know if these are M42 or M35 - I suspect the latter.Where the Drill Americas come up a bit short is in quality/precision of grinding, with two noticeable issues: The trailing face of a split-point bit should ideally meet the cutting edge at a point, though in reality all manufacturers leave a tiny chisel point to allow for machining tolerances (i.e. the split doesn't quite intersect the cutting edge). Those residual chisel points are noticeably (50-100%) larger on the Drill America bits than on the Chicago-Latrobes, though both are MUCH smaller than the chisel point on a conventional bit, and both are small enough to avoid wandering.A more serious issue is that a couple of the smaller bits are mis-ground such that the trailing edge of the splitting edge is almost on top of the bit's cutting edge, leaving a very thin flute.Both of the grinding issues are foregivable in my opinion both because of the low cost of the bits, and because the key benefits of cobalt bits is that they derive their hardness from bulk material properties rather than from a coating (oxide, TiN, TiAlN, etc). You can grind them over and over and they remain as durable as when new. If you have a Drill Doctor or drill-bit grinding fixture that can do split points then these are a no-brainer.I ordered two of these drill indices, one is the M35 and the other is the M42.I was intending to use the M35 drill bits for everyday use and was intending to keep the M42 for drilling into mild steel.These arrived in separate shipping parcels and once unwrapped and placed next to each other they appear absolutely identical with the exception of the paper nomenclature description tags. There is no identifying print, specification labeling, or markings on either of the drill index containers except the gold stickers and the paper label.Typically, with most 29-piece drill indices, the drill bits are in different uniform lengths but some of the drill bits in these sets are surprisingly un-uniform, wherein the largest 1/2-inch bit is shorter than adjacent smaller diameter drill bits.Each columellar drill index is also supposed to have an o-ring to seal out moisture and neither of the two which I received contains an o-ring.Overall, this appears to be an Untrustworthy Drill Index manufactured in China from un-substantiated and un-specified materials based upon the manufacturer's design packaging.I am opting to return both of these to Amazon and to purchase something of higher quality from another manufacturer.I have not used any one bit particularly much however I drilled through 3/4" metal with ease. I filled a oblong hole with weld and drilled through the weld to restore the hole without issue.Look no further! If you are thinking about buying these, don't hesitate. You cannot ask for more out of these drill bits, long lasting and the carrying case is super convenient. I wished the marking of the size of the bits could be a little bit more visible, but that's nitpicking. Easy for the manufacturer to improve on the next iteration that comes out.Those are the best drill bits I have ever bought so far. They cut through metal and hold their sharpnessI received this Cobalt bit set yesterday. The first bit I used was the 3/8" and using my drill press unsuccessfuly attempted to drill through 1/8" thick ordinary steel. Would hardly scratch surface. Next bit size up (25/64) went through very easily. 3/8" bit must be faulty or perhaps had already been used? I would be happy with a replacement bit but apparently there is no way to contact seller directly and appears I would be responsible for any return postage. I am not happy.Decent. So far they work well. Stickers on case are amusing. Rust proof case. The case is plastic so I hope it doesn't rust.Nicely made bits, but costly and no choice of selection of required size of bits