I found SoBH to be very short lived. At first great fun but soon becomes very predictable and less entertaining. The mechanisms work fine (apart from when trying to play horde type forces) but it really needs a background/framework to hold it together. IMHO it works well enough for battles between similar sized/similar equipped groups. it does not cope so well with few vs many, or heroes vs monster.
If you have a dedicated GM to run the campaigns, events, encounters etc as a semi rpg then it could be great (hopefully that is exactly what a world setting like Shadowsea will allow). In theory it should take what works well in SoBH and add the bits it lacks.
For my money Mordheim/Coreheim is better than SoBH, and Savage Worlds better still. I am looking forward to seeing Fanticide released as that looks like it will cover the same sort of ground in a new way.
BUT....big disclaimer here, I cannot comment on Shadowsea directly.