Best Firmware to downgrade to? Best CFW?

Hey guys,

I'm going to purchase an E3 Flasher downgrader for my PS3 and just wanted to know which firmware I should downgrade to and which is the best and why out of 3.55 and 3.41. My PS3's base firmware is 3.40, so I can go to either.

Also, I wondered if you could also let me know which CFW is the best, because I've only used GeoHot's 3.55 and a Keamw 3.55 one so I have no idea.

Thanks in advance! :)