Federal employees do not "want out" they want what they had. the FEHB or Federal Employees Health benefits existed (created in 1960) before the ACA was crafted. this program allowed for federal employees to have access to the BEST healthcare plans out there in which the government pays 72-75% of premiums. they decided to keep this system, just like all other employers had the ability to do as well.
unions only want out because they are being cowards to oppression. think about it...in the past a "good union job" came with premier benefits. now, employers can not offer employer based insurance that exceeds 9.5% of household income. they would pay people nothing and offer nothing if they could, but now they have to and it can not exceed a certain cost. if it does, people can join the marketplace to get a plan and forego their employer insurance.
i would ask why unions think their rates are going up? is it because the companies who work with unions feel they were paying too much for healthcare as is and refuse to offer insurance less than 9.5% of household income? is it because companies are basically telling unions to get bent and they are so weak and powerless they allow it to happen?
if unions were smart, they would accept the changes to healthcare and demand a higher wage. since they are voiceless, powerless, and usually corrupt to the core, they will instead choose to reject the policy and blame the government instead of the GREEDY industries and corporations who are holding this over their head. they do this to avoid a fight, because they have no spine.
i have yet to hear a decent argument for why unions are opposed to these reforms. for any who wish to inform me, i am all ears.