Similar to the 190, the 268 is an 8 day manual wound movement, but instead of JLC movement the movement is an in house (panerai) movement. Straightforward differences would be the addition of a date with cyclops and the power reserve on the front of the dial, also the lack of Côtes de Geneve on the movement.
Case of the 268 is thicker than the 190 by around 2mm, this seems very small but on the wrist its thickness is noticed. Movement is an in house P.2002/3 which also was designed to run 10 days total so that the first 8 would be most accurate. The P.2002/3 is a triple barrel movement versus the JLC double barrel movement but last the same amount of time on wrist.
Date is magnified by use of a 1.9mm cyclops UNDER the crystal, and power reserve is displayed as a "tooth" horizontal indicator. Differs from the 190 again as it has the power reserve on dial side versus movement side.
I personally feel the 268 is overkill when choosing an 8 day panerai.. the date function is nice but i do not like the power reserve on the front of the watch as it seems to always say 'wind me". The radiomir case can easily be worn with dressy attire or casual depending on the strap chosen. Winding the watch is not as smooth as the 190 but some might like this better as it gives better feedback.