A few thoughts on this, that might help you in your decision:

1. I would challenge your assumption, that "the jobs are otherwise similar". Something must be different between the jobs, so start off somewhere else: Where will you learn more? Where will you be the happiest in your everyday life? If it makes you miserable to leave 50k on the table - which would be totally fair - then go for A.

2. If B has a valid reason for the lower offer, or they can offer you something else (bonus possibilities, profit sharing, options, education), then go for that.

3. Thinking experiment: If you offer B, that you would work for them for 150k, and they say no - would you feel happy working for A. Would that be equally interesting?

33% below market level is a lot, so I would understand, if accepting such a low offer, would create some negativity in you. If B can not offer higher, it takes some greatly interesting future opportunities from them to make up for the lost salary. So no matter what, ask B for more, but be ready that they could say no, and take their offer away.

Given the information I would say, that it is really a question of your preferences. If you would like to discuss it more, so you become more aware of your preferences, give me a call.

Good luck with your decision.

Best regards
Kenneth Wolstrup