Imo if you want the SEM get the SEM. Whatever differences are present between the old and new one, I can tell you that the new one def. has the SEM sound.
Featurewise, I'd probably rather have the Boomer, so I think it depends if you're looking for (added) functionality with some OB flavour, or the very particular sound of the SEM.
“This is the most beautiful place on Earth. There are many such places.” Edward Abbey Desert Solitaire
Hardware synths: Korg Polysix, Korg Lambda, Tom Oberheim SEM, Moog Minitaur, DSI Mopho