Both cameras built in the same factory in Japan,imaging software,lenses,sensor,etc the same. The ONLY difference is the front case, which has the Leica logo including a different hand grip. Software you do get the adobe photo s/w with the Leica, Is it worth the extra £200?
TZ20 has an updated firmware (1.2)released 3rd August 2011. If you are considering the TZ20, try and locate the TS10 US version. Shoots Video at 60fps whereas the the TZ20 is 50fps.
PS: I bought the TS10.
"There are well to do people that wear Rolex watches, drive Mercedes cars and listen to Elac or Canton loudspeakers. That is the group that would buy a Leica.It is called class and that is often a misunderstood concept for some"