One by ten

I haven't used my big chainring yet this year.  And, now that I think about it, I haven't used my little one either.  So, today, I took them off.

One degree of freedom

It's better because it's simpler and cleaner, it's lighter, and it gives you more clearance.  It takes half an hour and it's free.
  
Both of the fastest bike riders I know (and all-around full dudemen) Ricky Federau and Neal Kindree, have been set up this way for quite a while now.  Neal crushed everyone at the Test a few weeks ago and Ricky can tango with the professionals and he's a professional chicken farmer.  That's not to say it's faster - Ricky and Neal (and not their bikes) are faster - but it is sufficient to say it isn't slower.


And there's no downside.  If you're going fast enough to use your big ring, you're probably coasting.  If you're going slow enough to use your little ring, you might as well walk.  


If you use your little ring all the time, I suggest taking up nordic walking or STOP READING RIGHT NOW and just go ride your bike.  Riding your bike will solve all of your bike-related problems and likely some other ones too.


On the other hand, if you don't use it, you don't need it and you'll be better off without.