The Sony PCM-M10 is generally regarded as superior to the Olympus LS-7 (better mics, quieter preamp, longer battery life). The LS-7 can be found for less than $150, the M10 around $225.
The LS-7 does have one feature that is very useful a particular set of customers: The ability to play back and record unattended, based on its internal clock.
Unattended audio surveys are a standard feature of research by wildlife biologists. Sometimes the presence or absence of a particular bird, bat or amphibian species plays a key role in the decision to permit development of a wilderness area. Unattended recording is preferred because it removes the chance that the presence of a human operator will affect the vocalizations of the target species. And unattended recording allows biologists to get a good night's sleep, instead of sitting outside in the cold, waiting for the time to switch on the recorder.
For example, audio surveys are a standard way to discover what frogs are present. "Froglogger" recorders are expensive, and designs for homebrew solutions are often closely guarded secrets.
The LS-7 changes all this. It has the ability to set three recording times daily for a specified duration. If the researcher wants to provide a stimulus, the LS-7 can also play back at preset times. For example, you might want to play a pre-recorded owl call for a minute, then start recording for 10 minutes to capture response calls.
The unattended recording feature is also useful for capturing a lecture. Just hand the recorder to a colleague who will attend the event. The recorder will start recording at the pre-set time without further action.