Personally, I'm happy with the health insurance that I have. It's provided by my job and the only coverage that I'd be able to get unless I paid out of pocket (and that coverage was bad - way out of my price range or offering virtually no protection). I don't expect the health care bill to do anything for my health care. If it lowers costs, my work will just pay less; they won't lower the amount that I chip in, although it's possible that it means that they won't raise it. But it took me ten years to get this.
The Republicans don't necessarily hate competition. They simply think the public option isn't genuine competition, isn't intended to be so, and is nothing but a subterfuge for an eventual single payer system.
One way in which a company can obtain/enforce a monopoly is to underprice a good so much that competitors can't match it because they're either damned with (1) charging a price where they are forced to eat of loss and go under or (2) not match the price and lose the customers anyway. The monopooly company can do that because they can eat the loss and still survive.
I'm not saying the Dems intended to do that, but, on the other hand, what's to stop them? The government's one entity that's not required to produce a profit. It doesn't help that some Dems, like Barney Frank, have said that a single payer is where they'd like to ultimate end up.
As Nick mentioned, the Bill susidizes those people. The fine itself is problematc though. Insurance companies want it high for obvious reasons. The higher the fine, the more incentive there is to buy insurance. They got pissed off when it was low because if it is below the cost of the premium, you'd pay the fine not the premium. This course was further incentivized by the portion that prohibits rejecting people because of pre-existing conditions.
If they cannot turn you away because of that, would not you incentive be to pay the small fine and then when you get sick, buy the insurance? It's a disaster waiting to happen for any insurance company because it minimizes what they make in premiums and maximizes what they pay out. Naturally, this would push premiums up and would be a sure fire way to force all, but probably the largest of insurers, out of business.