There was a test on the Delta 400 (as opposed to 400 Delta) in the British Journal of Photography last week. Geoffrey Crawley said that it had more latitude than the old Delta (appeared therefore to be faster. In fact it was very similar to HP5+ in its chracteristics, but with the typical fine grain of the Deltas. He thought that most HP5 users would prefer the new film. If you tried the old Delta and did not get on with it then you might like this. It also pushes like HP5+ and has finer grain. The old 400 Delta did not push very well.(posted 8761 days ago)It has two emulsion layers (like Delta 3200)and handles highlights better.
None of this is personal experience, but it certainly looks like an improvement.