<p>I own the 35mm f/2.5 Summarit and the 35mm f/1.4 Summilux ASPH FLE. Both are outstanding, with neither being significantly "better" than the other. What the Summilux is, is faster, not to mention a lot heavier and more expensive. If I'm going out for just the day or with just my M Monochrom with its 10,000 ISO ceiling, I usually just take the Summarit. For longer trips or when I expect to shoot a lot indoors or at night its the Summilux. Sometimes both, with the slower lens on the M Monochrom and the faster one on the M-E.</p>
<p>With the exception of unanticipated available darkness, I've never wished I'd brought the other lens with me.</p>