Like Pygathrix, I have visited both the Aspinall parks' cages and the congo gorilla forest and so I shall try and give a fair comparison.
First, what each is better at. CGF is obviously a better immersion exhibit, the fashionable style of design, at least for the near future. It provides a more natural environment for the gorillas (although I think a lot of this is setting the scene for visitors) and is more informative. It gives the gorillas a large area, demonstrates how they fit into their environment ecologically and has given the Bronx Zoo a world-class, boundary pushing exhibit.
Next, the Aspinall parks, I have spent a long time observing gorillas in both environments and, although I am no epert in gorilla behaviour, I would say they acted more naturally at Howletts. The Howletts gorilla cages are cheaper. They provide an imortant canopy, lots of enrichment activities and a wealth of climbing structures. Also, in Garden of the Apes, taking photographs is easier as there is no glass / bars.
Now to down-sides. CGF was expensive! Zooplantman would not reveal the true figure but it is certainly a lot more then the $40 million originally intended. This means that it is unlikely to be replicated by any zoo in the near future. It does not provide the same canopy cover as the Aspinall parks (although certainly more than most). Although it is a large size, I have read somewhere that Gorillas tend to remain at least 3 feet (or some similar figure) from hot-wire, which drastically reduces usable square footage. Also, there are far less climbing structures for the gorillas then at Howletts and none of the deep litter in which the Gorillas like to forage.
And now, Americans, it's the time you've all been waiting for - downsides of the Aspinall enclosures! They are ugly (although rather majestic), and, for the cages, visitor viewing is impeded. They do not provide the visitor with a sense of the gorillas natural habitat (although they do show how they are adapted to it) and there is certainly not as much or as good interpretation as there is at CGF.
So a conclusion, well looking at the evidence I would have to say that I agree with reduakari, zoos are about conservation education. Welfare of animals is, no doubt, important but, in my opinion, simply saying "the animals are well cared for" is no justification for zoos of the 21st century. Therefore, I will always find myself swinging towards the Bronx's world-class exhibit as it really gives a sense of the African rainforest and the Gorillas appeared to be content and well cared for. However, I will say congratulations to the runners-up. The Aspinall parks will nver be able to afford a CGF so they have created a substitute in which gorillas delight visitors by acting as though they would in the wild.
But, as ashley-h said, just my $0.02.
1) I have seen pgotos of gorillas resting with their young right up against hot-wire so it doesn't take up usable space. Keyword, you "heard" and you can't believe everything you hear.
2) How do the bronx exhibits not provide a canopy. Almost the whole exhibit is covered by lush foliage above creating a natural canopy for gorillas.
3) The apes don't do anything special at Howletts that they don't do in Bronx. They forage through grass (which there is a lack of in Howletts), make hay beds up by the windows, climb on logs, and go to hidden feeders where their keepers hide treats in. So Please tell me what is it that they do at Howletts that is so natural? At bronx there is plenty of interaction among the troop so don't use that to support your arguement.