[Plugin: Yet Another Related Posts Plugin] Clarification on version 3.2

Just upgraded Yarpp to 3.2 and haven’t done any changes to the settings, everything is working fine.
1.In the Changelog, you mentioned ‘Better caching performance’. Does this apply only when we select object based abstraction for caching (postmeta) or is it on the whole?
2.As such, do you recommend using ‘postmeta’ (adding that piece to wp-config) or leave it as it was in the previous versions (custom database), for better and less server straining performance?
3. Do you think, ‘postmeta’ thing works with themes like thesis, which uses custom meta like thesis_title, thesis_meta etc?

Thanks in advance for your answers.