The old Fluval internal filters were great (Fluval 3plus, Fluval 4plus, etc.). But I don't like the new line nearly as much. The old ones had a simple foam insert and worked great. The new ones have dinky slide-in cartridges with less overall media.
On a large tank there really isn't a reason to go internal, with all the HOBs out there (I would go with an AquaClear) and canisters (I would go with a Fluval) there are better option.