I use ClassicUO personally as it suits all my needs, I use ClassicAssist which is like Razor but is developed to work well with CUO.
As for Orion correct me if I am wrong but aren't the macros coded using Java?
I have a few scripts on Orion which do not work on any other helper like Razor, UO Steam, ClassicAssist, etc.
Auto tree harvesting and auto mining.
I'm sure with a lot of work they "might" be able to be converted but I've never looked into it..
I also use Orion for testing as it's always nice to have an alternative client and there are in fact a few bugs with ClassicUO that Orion does not have, for example building a house is painful with CUO as it takes a few seconds to update each placed block, this does not happen on any other client.
i downloaded the classic client, added razer.exe as a plugin but it still doesnt load when i launch the client though
If you had already created your shard login then you need to ensure you enable the plugin in the settings:

Then save the profile.
Also how did you add it as a plugin?