Both have their pros and cons. I like the squadron atmoshere, flying low levels at 450kts and flying tactical every day all day. In the T-45 I try to get inverted at least once on every flight.
Flying the big jets can be no less demanding on short haul, long haul it can be demanding to stay awake, but that's where the money is and the lifstyle. Flying for the military usually involves alot of other stuff beside flying, and flying heavies really isn't flying, but is system management instead.
Would would be the best? Flying fighters every day, non combat,without a ground job, but getting paid as a senior airline pilot. That job does not really excist. Test pilot for a defence contractor may come close, but then you still have a bunch of reports to fill out.
Again, as far as flying goes, fighters by far, but I left being active for the long haul airlines, what does that tell you?