I guess Tarkan was using a 7gen, and with everything at stock 5th gens had only 14 hour battery life while 7g had 36, so one would expect there still to be a signiifcant difference (though I'm not clear how much that difference was down to the motherboard circuitry and how much to the different hard drives - as only the former effect should still be relevant).
All the same, for all models, in theory the reduced life due to the ssd power draw should be more than made up for by the far larger battery. But possibly rockbox plus different volume/backlight etc would complicate that.
@frigomax
Have already been wondering if I should have ordered the Crucial (M550) rather than the Samsung. Now you've added to my doubts! On the other hand, I've seen others say the Samsung worked for them but the Crucial didn't!
There's an awful lot of trial-and-error about this process!
Haven't seen any experiences with the M550 in an ipod (rather than the M500) but all the benchmarks on-line say it uses significantly less power than the m500 so I'm thinking I should have tried it, if only to have some new data to contribute to the discussion!