Bofa giving a rate of 2.15 right now (till 10/28 I think). I do have more banking with BofA due to which I got additional discount. Could not find any other cu around seattle greater area that gave lower rates.72 months vs 65 months, better user interface (credit unions typically have bad UIs since they're cobbling together various off the shelf software), and in order to get the best rate with DCU you need to setup direct deposit with them (doesn't have to be for your entire paycheck). So people would tell DCU they were going to setup DD to get the low rate on paper, then go back to Tesla who would match you with a bigger bank.
Personally I setup DD with DCU a while back in preparation for our Tesla so we're just gonna go with them for our loan. Not needing a down-payment is nice too.