The former Lutherans, former Anglicans and former Roman Catholics are my favourites, they typically make the transition smoothest.
The former assemblies of God, former methodists and former charismatic episcopals try my patience !! no thanks !!! (shudders in fear)
These ones often seem not to adapt to the "higher smells and bells" of the Orthodox Church as easily but are very much alive and on fire with the faith otherwise.
I've heard that the former WR Orthodox in RC "personal ordinariate" anglican use churches are also interesting to meet
Each WRO church is entirely different, but one can expect a decent number of all of the above.