Swings and roundabouts pjam. This game can be very fickle and many have paid the price for taking a wrong turn, just as many others have profitted from taking the right one.
2 mates of mine joined Ansett back in the early nineties, (post AFAP ban). Both progressed from the F50 as F/O's onto the A320, again as F/O's. As movement off the Fokker was relatively rapid, commands came up on the turbo-prop fairly quickly, and both were offered left seat positions back on their previous equipment. One chose to take it, the other decided to stay put as he felt an offer of command on the bus' would not be far away. A short time later Ansett disposed of the F50, and the pilots retrained onto other jet equipment. Many of the F50 Captains were junior to those that stayed on the jets as F/O's, but because the commands at Ansett were perpetual, irrespective of type or seniority, the Captains on the now defunct Turbo-props were given priority of commands over F/O's on the jet equipment. The old mate who chose to stay on the A320 spent the rest of his career with Ansett haveing never made command!
I guess the morale to the story is, try to be totally familiar with what the results of a change will be. If it goes your way, great. If it doesn't, at least be comforted by the fact you may have "gambled" and lost!