Simon and I own the 35mm Leica Summarit and Summicron lenses so we decided to do a quick test to compare the two.
You can see they're pretty close! Only the depth of field is slightly shallower on the 'Cron which is to be expected since it is 2/3rds of a stop wider. For half the price of the Summicron, the Summarit is definitely no slouch.
While you're here, check out the Australia Leica Collective.