My parents bought a Sigma home. Completion was around six months late. When they moved in house was unfinished. They have tackled all the snags but has been down to my elderly parents to spot snags and get them done, often after a lot of feet dragging from Sigma and back and forth. Based on my experience I would avoid buying a home off plan if you can. Maybe Sigma no worse than anyone else but it was very stressful. Positives are location, design and general layout of development which is nice. Workmanship on finish was sadly lacking. Kitchen cheap with moulding on doors already failing. Same experience for most in the development.