I would honestly, if you look in getting you're project big, and Proffesional, The latest Aspire NCDB Cores/Repacks are the most stable, Arcemu = 57% stable, Ascent 74% stable, Aspire is 85% More stable, And 25% Less buggs,
Although, you should have gaven and option of Mangos, Mangos is the best Running WOTLK Database/core i've seen so far, it's not very flexable, but VERY Stable, and complecated to modify