Which one to pick?

To me the seem to be all the same truck. Pick the one that grabs you and go.

 

Hmm, which ISX's are in each truck? If any have the CM871 ISX (DPF but no DEF system), be prepared to clean that EGR system up and KEEP it clean otherwise it will haunt you. No experience with the newer ISX with the SCR system (gotta fill it with DEF) so I can't comment on those.

Also what are the driveline torque ratings, are they all 1650ft/lbs or are some 1850? Not that you need it for pulling max 80k, but given the choice I'd opt for the heavier driveline, nothing wrong with some extra strength, though it will probably add some weight. As far as I know the ISX can be rated at 1650 or 1850 at those HP ratings so it just depends.

With 3.55 rears on the 587 I'd be looking carefully to see how the 18spd is set up, if its a single or double overdrive, etc. I wouldn't want my cruising speed to be in an overdrive gear for mileage reasons. Same with the T660s, is it a 10spd direct or OD?

If the T700 is set up with a 10spd direct, its probably gonna be the best truck for fuel mileage. Although the T660 is the best looking of the bunch IMO but that 18spd on the Pete would be real nice... guess I'm not helping that much LOL but maybe some more things to consider about each truck before making your decision.

 

Do plan on going to commiefornia? If not why looking at newer models for it's not if it's going to break down but when and how many times will it be in a shop for repairs. Me I wouldn't consider any thing past 2007. Sure there are some guys who haven't had problems with the newer trucks but there isn't to many of them. And if it's covered by a warranty it still will cost you something always does. Either in lost loads or money for something not covered. Get what you want don't settle for something just cause it's close and there will always be more trucks brought in don't rush out to buy take time and buy wisely.

 

Between all of them I think its between the t700 and 587. Your next step should be to check the mechanicals of your top choices and oil samples (unless done already.) With the new trucks its really just luck sometimes.