The difference is precisely what you quoted. The L2 Cache is different. The first one is a Dothan chip, it has twice the Level 2 Cache (extremely fast ram that can be accessed by the processor QUICKLY) compared to the other one.
So in all cases, in any application, the first one is going to be faster, #1 because it's got twice the cache, and #2 because it is 200 MHz faster. In the long run you'll be happy you popped for the Dothan chip.
Intel Pentium M Processor 735 1.7GHz (32KB L1, 2MB L2 cache)
Intel 710 Centrino Mobile 1.5GHz (32KB/8KB L1, 1MB L2 cache)
They are on two different machines I am considering (amongst many I have considered). Other specs on the machines are somewhat of a non-issue as they are too close to each other. Both units would have 512 MB of RAM and 64 MB dedicated video. They are both Toshibas.
I am looking for as much power for office-type applications and multitasking as possible (within a specified budget)...and battery life and portability. I could go to a P4 HT or AMD 64 for a little less in cost, but I have found those machines to be quite heavy to carry to and from work on a daily basis.