In California, my Blue Shield HMO has “medical groups”. If I want to see one specialist in one medical group and another specialist in another medical group, I cannot. I have a primary care physician that is working with me on my diabetes, because I hate the two endo’s that are offered and I love my nephrologist. Call their offices and verify they take your HMO plan before you commit to it.
I would personally pay an extra $300 per month to be able to see whatever physician I want to, assuming there are really no restrictions. If you can see the specialists you love with just an extra office visit to a PCP, save the money.
Another thing to consider is on the plan choices I have as a California government employee is out of pocket expenses that would really add up for someone like me, or for catastrophic expenses. Like I pay $50 for an ER visit unless I am admitted, and then I pay nothing. I was unexpectedly hospitalized a couple of years agofor 12 days, It didn’t cost me a penny, but on the other plan I would have paid $100/day. Not a ton of money, but I also couldn’t work for about 4 months, so every penny counted.