Cool - so lets run some examples.
In the extreme good case - $0 health expenses, the HSA wins due to the lower premium + 1200 into the HSA which is basically more income that you get to keep if you don't spend it.
In the extreme bad case - Say an ER visit + hospital stay where the bills are 100K or something, the HSA wins again - the lower premium + employer match outweighs the difference in out of pocket maximum.
In the middle, it gets more interesting - say you've got 2 ER visits for 2 different people that sum to 5K - in that case you've got the following:
PPO: $500 deductible + 20% of 4500 = $1400 out of pocket
HSA: $3000 + 20% of 2,000 so $3400, so that nearly wipes out the guaranteed savings of the HSA plan. However if you had this bill, I'm guessing you'd find a way to deposit $2200 more into the HSA and pay the bill with that, thus saving quite a bit on taxes.
But if you just have a lot of office vists, the PPO looks better - say the 5K is 6 regular office visits + 18 specialist visits.
PPO: $60 (you'll go to one of the preferred doctors mentioned, right?) for the regulars + $360 for the specialists = $420
HSA: 3K + 10% of 2K = $3200 which is nearly $2800 more.
In reality, you'll have a mix of office visits, labs / tests, maybe an ER visit or two, so it is murky. Some places offer a calculator to help estimate these things - you'd input your expected office visits, various tests, ER visits, and other costs and it tells you what each plan would cost.
If you can maximize the HSA contributions for the year, and you've got a fairly high marginal tax rate (remember to include state income tax if applicable), then I'd personally take the HSA and maximize the HSA contribution given these options. The tax savings from maxing out the HSA narrows the situations where the PPO would come out ahead, particularly given that the HSA is the better choice if you have that extremely high health costs year.