The big difference here is that the 2448 is inline so you have both tracking benefits (confidence monitoring and starting to build a mix without committing EQ to record path) and mix benefits (second set of inputs at mix time per channel). Both have a single 500 slot per channel, both have optional automation packages. Both will cost double the Trident 88 per channel at least, depending on options. If you already have a large investment in 500 EQs and compressors (or want to), it might be worth going that route. Note that newer 2520 opamps have a tendency to fail, and you will have lots of them in either console. The good news is that there are dozens of options for replacing them (including the CAPI 0252, which by many accounts sounds closer to the older 2520 than API's current version).
You should probably schedule a demo of these if you are considering them seriously - either at a local studio or using API's virtual console experience. At some point, you need to use one to get a feel for what you like and don't like. Don't only listen to internet people (like me). 🙂 Also - study the block diagrams to really get a sense of routing options - this is an area where consoles really differ from each other.