Presumably the 2.8 was designed from scratch to run with a DPF, though how suitable your use would be to keep the DPF happy is for you to decide.
I understand from the John Cadogan's youtube channel that due to numerous DPF issues the latest models now have a manual regeneration mode via driver operated switch, i personally think is an excellent idea, whether this would be able to be retrofitted to a UK model i don't know, but might be worth investigating because it puts you in charge (as in many trucks where driver can cancel or trigger regen when suitable) of when and where the thing regens and not this pot luck method used in most cars.
As for which is better, only you can decide by test driving, we all drive differently so each of us require a different driving experience, i myself am happy with how the 3.0 litre drives, but then i haven't test driven a 2.8 and will do my best to avoid DPF's for as long as i can.