The thing I'd wonder is how much of an upgrade are these bikes over your Smoke. I totally understand wanting to get a new bike, but I wonder if you wouldn't get more bang for the buck out of upgrading the components on the bike you have (assuming it fits and is comfortable).

I was just poking around a few of my favorite web site, and it looks to me like you could upgrade your whole drive train to Deore/LX level and get some hand-built Deore/XM317 wheels for around $400. This is assuming you could install the parts yourself, but if your open to it, I think you could. If you buy one of these new bikes, you'll spend at least $400 and still have Altus level components.

Of course, this brings us to what you mean by efficiency. Components aren't everything. I think you'd feel a big difference with a 9-speed drive train and a carefully chosen gear range, because it would get you tighter spacing between gears. Lighter wheels would also be quite noticeable, and though I know clydes are concerned about wheel strength, a well built 32-spoke wheel is going to be plenty tough enough for you.