Hrm. I happen to think that 340% is a pretty respectable gear range. Remember that a typical 70's 10-speed (with 39/52 cranks) had a gear range of about 267%. If we're generous, and give it a 34-tooth freewheel cog, that 10-speed has a range of 324%. Not really suitable for touring, but pretty good for anything else, I think. No, it's not at the 500%+ range that a derailer system can manage, and I think that's a good reason to prefer derailers for some purposes. It is getting closer, though, and for most applications, 340% is as much as anyone could ever need, I think.