Definitely 309/100 if you don't need to go right now. Much shorter wait times and he would be able to go straight to PR meaning you don't have to deal with the constantly changing partner visa crap.
Not only are jobs difficult on temporary visas onshore, but he'd also have to pay and apply for another bridging visa if he ever wants to go offshore for holiday or visits. Wait times for 820 onshore can be very long, with some people currently at the 2 year mark (though that's not common, it does happen). He could still go straight to PR from an onshore app but it is likely to take much longer due to wait times.
Not only are jobs difficult on temporary visas onshore, but he'd also have to pay and apply for another bridging visa if he ever wants to go offshore for holiday or visits. Wait times for 820 onshore can be very long, with some people currently at the 2 year mark (though that's not common, it does happen). He could still go straight to PR from an onshore app but it is likely to take much longer due to wait times.