Baked GI in real world use...

I haven't been able to use BakedGI with any success, LONG baking times, differences between SCENE and game views making it difficult to previsualize, many 3rd party assets (fog, etc) don't see to work, and most importanly a huge number of lightmap glitches.(black patches, blotchy shadows etc).

What has been your experience? Do you use BakedGI regularly, and if so, what are your typical settings and or tricks to get it to work?