I've been enjoying my CF-54 with Fedora 23 lately and this battery life amazes me every time. I can run this almost full day easily and carrying plain thing without power supply make life easier anyhow.
I also acquired second HD cradle while back, making my upgrade routines easier. This whole HD cradle was actually the thing which drove me to Fedora 23 testing, because I could leave my 'operative' setup on self intact while trying out something new.
After all, I've been really satisfied for this setup. Running Linux on Panasonic Toughbook CF-54 is so far best experience and our company does this on multiple users with toughbooks with no issues.
Sticker on this one should say "Panasonic recommends Linux".