Check those still-relevant trip reports from the FT archives:
http://www.flyertalk.com/pasttalk/ft...ML/002424.html
http://www.flyertalk.com/pasttalk/ft...ML/002873.html
I personally find PR's C seat spacious enough, but certainly not class-leading. As for the sometimes 'cheerful' atmosphere onboard, a little familiarity with Filipino culture can help.