We have the Hemishpere version of your unit and the floor plan works really great for us (although a little more room in the bedroom to move around in is the only complaint) I wish they would put a small slide in the bedroom.
I believe the Hemi is a good upgrade, and it's not just the fiberglass exterior. True it is easier to clean, but the aluminum framing and lighter weight are also benefits.
I don't know if your std Salem has these features, but the Hemi's come with enclosed underbelly to keep and protect your components, the heat duct goes through this also, but while Forest River touts it's a heated underbelly, it really isn't. Hemisphere's also have a radius interior ceiling which makes it look and feel a little more spacious (again I'm not sure about your unit). We looked at the std Salem version of our 282RK and decided for the extra $$ we'd get a structurally better unit, a little nicer furnishings, and better resale or trade in value. the bedroom is also laid out with a dresser and wardrobe at the foot of the bed against the bathroom wall (the Hemi is a foot longer than the std), and a hinged bedroom door. We had the option of an outdoor kitchen which we declined in favor of more storage.
I think you did well with your unit, and I don't think you could go wrong with the Hemisphere either. MHO.
Mark, Vicki, & Scout THE dog
2015 Hemisphere 282RK
2010 F250 Super Duty
1992 Goldwing Aspencade