Looks like going with the HSA you'll have premium saving of $574 (assuming those are monthly premiums) and tax savings of $3500 times your marginal income tax rates. Don't forget to include FICA savings if applicable under your employers plan for HSA payroll deduction. How much would that be for you?
The premium savings more than make up for the $500 out of pocket maximum increase under the HSA plan, so if you end up with high medical expenses one year the HSA plan is at least somewhat better. If you end up with very low medical expenses the HSA plan is also obviously better. So having a medium level of medical spending is the only way the other plan is better, which is pretty typical.
Say you had $3500 of expenses. You'd spend all $3500 on the HSA plan minus $574 premium savings for a total of $2926, and $500 deductible plus $300 for a total of $800. So the other plan would be $2126 cheaper, minus your tax savings on a $3500 HSA contribution. You might save a little more with the other plan if some of the spending was covered by copays instead of the 10% deductible, but other that that, I think that's just about a bad as the HSA plan could get. Under higher or lower spending the HSA plan probably starts doing better.