You can get a Dahua Black Face PTZ w/a Starlight image sensor for about $500, vs $350 for Huisun/Sunba Speed Dome.. that $150 more will get you much better quality all around.
dont be penny wise and pound foolish; after the Huisun/Sunba SD goes kaput you'd of spent far more money in the long run than you'd had if u just avoided cheap junk in the first place.