In the early 2000's it was Dip (330HP), Dynasty (400), Exe (500+), and top of the line Sig (500+ HP). Diplomats are non tag (RR8R) and the rest are tag and 10 airbags( RR10S). In those years a Dynasty gave the most bang for the buck as an Exe is pretty much just a Dynasty with a bigger engine (nice but not necessary) and a fancier ceiling plus some options standard.
The Sig got the bigger LR slide in 2002, Exe in early 03, and Dynasty in late 03. Four slides did not start until 03.
By the mid 2000's Monaco, Beaver, Safari, and HR were all pretty much the same with different engines. Monaco and HR came with Cummins (an exception was an Exe with a Detroit). Beaver's came with Cat engines and in the higher HP was not a plus starting in 05 with the Acert engines.
The newest Monaco (#3) just came out with a Dynasty that no longer uses 10 airbags and has IFS. Monaco #2 still had excellent customer support... no idea about #3 but the customer support 800# is still active.