BDSP for me. I'm sorry, but it was pretty much a carbon copy of the original Diamond & Pearl. It didn't offer a new experience to the Sinnoh region like other remakes did, and the very few it did was in the Grand Underground and post-game. Then there is poor game design, such as not enough influence from Platinum and inability to get some Sinnoh Pokémon during the main story either because their evolution items aren't available until post-game or the Pokémon themselves aren't available until post-game.
The last bit urks me more as I was one of those people who had to jump through hoops just to use a Sinnoh Pokémon in a Sinnoh playthrough, adding on to the amount of people I've seen during the lead up to these games that were keen to use Pokémon like Gliscor or Rotom on their teams.
Apologies for the small rant there, but overall, these games are fine for people who have never played through Sinnoh. But I think it's fair to say that Platinum still offers the better Sinnoh experience.