Be careful if buying imperial cobalt drill bits, there was a whole bunch imported from I don't know where about a year ago, they totally flooded the market, some even ended up in the RAF toolkits, they were absolute crap, those that didn't burn out, gave you oversize holes with burrs to take your hand off.
So if you want imperial drills, go for a known make that has been recommended by someone you know.
Remember - You have been warned!
Generally though they are the dogs, but by 'eck them small diameters are easy to break!