A2589

There are merits to both checking and betting, but I'd check. He will let you know on the river if he has a good hand or not and when he doesn't, you'll take the pot down by betting quite often. You have stronger hands here like A2+two pair that you can bet intending to get in.

I can go either way, but I tend toward bet. With a check, he can't be too strong, and we have a pair and are open-ended, obviously.

If SB doesn't check range but instead leads with some (or many/all) of his good hands, betting indeed becomes much more enticing.