Unfortunately my insurance premiums have gone up since Obamacare so I would say I am against it but the truth is, I don't know exactly what it is just that it costs more.
One of the main reasons for the increase in premiums is because of the mandate to cover pre-existing conditions at the same cost as those without that condition. No other form of insurance allows you to get coverage after you have a reason for a claim; you can't get into a car accident, then purchase car insurance and have that insurance cover that "pre-existing" accident. The way that insurance is supposed to work is that you pay into it in case at some later date you need medical attention, the insurance company can pay for your medical costs. As lbryanwf mentioned, it is in a way like gambling... You are betting against the insurance company that at some later date your health costs will exceed the amount of money you can easily pay for, while the insurance company is betting that the premiums you are paying will exceed the amount of health costs they'll have to pay out. As long as people have health insurance and are consistently paying for it, then the insurance companies should be able to cover for those catastrophic events. But once you force insurance companies to cover pre-existing conditions (esp. without increasing that person's premiums above the rest of the pool), in order for the insurance company to stay profitable, they have to increase the premiums on the rest of the members in order to pay for your known costs.
The problem that lead to this mandate is two-fold. First, some insurance companies would drop your coverage after you had some high-cost claim. And then once you were dropped, it became more difficult to get new insurance because that claim was now a pre-existing condition. Another problem was that some people were losing their insurance when they lost their job, and when they were able to get coverage again, they were caught with having a pre-existing condition.
There are ways to reform our health insurance system solve these issues without forcing insurance companies to cover pre-existing conditions. First is to have automatic renewal of insurance. So as long as you are paying your premiums, the insurance company has to automatically renew your coverage. This would prevent insurance companies from dropping people once they have made a claim. Also, the insurance should be bound to the individual, not the employer. Tax relief should be given to individuals that purchase health insurance instead of other way around. This would alleviate the costs that business has to pay for their employees, and they could pass that savings onto their workers in the form of a higher salary which the worker would then use to purchase their own insurance. This would allow the person to keep their insurance whether or not they are employed by their current employer. It would also allow the beneficiary to choose what form of coverage they desire. A young person out of college may choose to get a low premium, high deductible catastrophic coverage with the idea that they are healthy so they most likely won't have any claims, and they can save money on their premiums to pay for other, more immediate costs like college loans. Whereas a person in their 40's may choose insurance that has a higher premium, but a lower deductible knowing that they will be needing to go to the doctor more often for things like colonoscopies and breast / prostate exams.