That is an interesting question. From a pure basketball perspective, assuming good health Blake probably fits the team better. Aldridge's game is in the post and the mid range, and I am not sure how well that would mesh with Horford on the floor. Blake on the other hand is capable of getting to the hoop, and has demonstrated better range out to the three point line. His defense isn't great, but if you have Aldridge either he or Horford is going to be checking someone on the perimeter, and I am not sure Aldridge/Horford is better than Griffin defensively matched up on a quick or athletic four.
However, other considerations favor LA. Namely, health, contract situation, and 'intangibles'. While I am not sure there is a such thing as a 'minor' heart irregularity such as Aldridge had last season, Blake has had tons of injuries through his career and Aldridge has, broken hearts aside, had a stellar injury record for a man that large.
Furthermore, Aldridge's contract expires in two seasons, at which point he will likely take a pay cut as a 33 year old. Contrast this with Griffin, who going to be a 28 year old with a significant injury history and almost certainly getting a maximum contract. There is big risk for Griffin turning into a massive albatross. Worst case scenario for Aldridge is it doesn't work out and after one season he becomes the all valuable 'expiring contract' to make trades and such work.
Finally, there are the intangibles. Specifically, Blake seems to disappear in the playoffs. In addition, he seems like an ass and I would not enjoy rooting for him. Thirdly, I loved Aldridge in Portlandia. Finally, I just find Aldridge's game very aesthetically pleasing and love what a throwback it is in today's NBA. Dunks are nice and all but as I grow older and more mature I am coming to savor a nice 18 foot jumper coming out the hands of a seven footer.