I will add this on a drum cooker - cooking over naked coals does impart a different flavor than in an offset. Grease fired smoke delivers a certain profile that's a major hit for many folks, and a major miss for others. I actually find it too strong a flavor note every so often, and am myself looking forward to a new SQ36 on its way to me as I join the legions of stick burners.
Some folks do put in baffles between the coals and meat to guard against the grease smoke flavor. I never tried but may one day.
The only downgrade is in cooking surface from your offset. Otherwise, you will gain incredible temp control and stability, and portability you don't currently enjoy.
I wouldn't get rid of your offset until a year or two of happy ownership from a drum. I also think you'll always miss your ol' rig if you do sell!