obie's are pretty reliable so if it's full refurbished i wouldn't worry about that too much.
also, the semblance and SEM don't sound identical. the semblance sounds great and has some great features and little differences that the SEM doesn't have. i had the semblance (1 voice version) and i like the way it sounds and the filter is cool and has some nice tricks but i didn't care for the knobs/pots. very plasticy feeling and some of them rubbed on one side or the other but it did sound really nice and had a great PW and it's pretty easy to get something out of it fast and it can be a very inspiring/surprising synth... but i'm sure a real SEM can too.
one other thought.. there was some mention of mr oberhiem making a new SEM w/a new company sort of like DSI though the new SEM will be just like the old one.
i think it was in a NAMM thread where that was talked about and there was a pick of tom oberheim standing next to dave smith and roger linn.
anyway- i ended up parting w/the semblance to get more modcan modules. other than the knobs/pots it was well made in a nice case and sounded good.
AS is making a semblance w/all the patch points brought out to the right on a faceplate called the Telemark.. pretty cool.
http://www.analoguesolutions.com/