I have my own personal opinion of the ACA but I've worked hard to set it aside for the comments I'm about to write, so nothing is written with the intent to start a political discussion - these are simply my observations.
As a freelance CPA, I work closely with a number of small businesses. I'll admit the sample size is too small to draw nationwide conclusions, but the observations are noteworthy (IMHO). These are the facts (for my clients at least): (1) the rates of increase in the premiums they are charged for health insurance for their employees has grown significantly in the years since ACA passed (versus the immediately preceding few years). (2) The carriers are saying that the increased mandates with the ACA are a driving force behind the increased rates of growth. They are also saying they expect that to continue as more mandates become effective. I can't prove these statements are true - but I can attest to the fact that this is what they are directly telling me. Even if this is untrue (and they're simply using the ACA as an excuse to charge more) it doesn't change the fact they my clients rates have significantly increased. (3) The penalties for not covering employees are small compared to even the most basic, "inexpensive" health plan (in fact the penalty is $0 if less than 50 employees). I've personally participated in planning meetings where it's being contemplated to cease offering coverage when the exchanges are set up. They plan to increase the pay to the employees (to help them pay the premiums for the policies they acquire on their own) as a part of the plan to drop coverage.
I believe (although I'm certainly biased) that my clients genuinely care for their employees and don't want to cancel coverage, but as the mandates of ACA continue to drive up the premiums (which is what the carriers are saying), they may be forced to drop coverage. It's not greed on their part (especially since they want to increase the pay rates to reallocate the "savings" from not paying health premiums) - it's economics.
Whether you like the ACA or disapprove of it, all must admit (IMO) that the market will respond to the changes in the health insurance environment. Perhaps the changes will be positive for the over-all health care/insurance market - I guess we'll all find out soon enough. But from what I've seen, it'd be folly to assume that since you get your health insurance coverage from a private employer that you're not subject to potentially significant changes due to the ACA mandates.