Hello Toby,
However, reading the manual and the limiting requirements for the user determination for the angle of incidence of reflective and liquid boundaries seems like quite a limitation. In practical applications I don't see how this is really possible, especially for complex harbour geometries. Furthermore, an error on the outgoing wave direction at the liquid boundary would surely lead to unwanted reflection throughout the domain leading to vastly wrong results.
I guess the ARTEMIS manual has not been updated for *quite* some time. All of the above mentioned limitations have been addressed over the time. Reflective incidence angle has, since many years, an option to be automatically derived and I can't recall "unwanted reflection at the liquid boundary" being a matter of serious, if any, trouble.
If the above are your only concerns, then by all means, give it a try. There are may other upgrades/features that are not documented at all. FYI, I've used ARTEMIS in 10+ real case scenarios.
Regards,
Costas