I've been holding off a bit on reporting on the SDS100 performance, because there are some issues that are being worked through (in firmware) that do affect reception of EBRCS... but so-far, I can't say that I see any problems that are obviously related to LSM.
My only comparison is an old BCD396T, which works fine in some areas around here (Brentwood), but seems to get confused in other areas, which never appeared to be related to signal strength - the "bars" would jump between full strength and nothing, and it'd say "Finding control channel", or audio would sporadically get garbled while driving around. It was generally unusable when out'n'about, but somewhat usable at my home. I assumed that those issues where due to simulcast, but never really proved it. The SDS100 seems mostly usable in most places I've gone - including most of east Conta Costa, and a bit around Concord and Livermore.
I will say that the Unication G5 receiver on 770MHz is definitely superior, so if you're in a marginal coverage area, and can live with the limited functionality, the G4/G5 would be a better choice, IMO. Central Contra Costa simulcast is solid in Brentwood with the G5, where the SDS100 either can't decode it at all, or breaks up a lot (depending on conditions, I guess) - using the same outdoor antenna.
Are there any particular areas where "y'all" have had issues with simulcast? If I happen to be in/around those areas, I could take the G5 and SDS100 and see how they do.....