Bolt assemblies rarely fail. That one is prob as good as any for $$ if you plan to drop it in a mainstream AR15 but I have not used it. Just in case Anderson Manufacturing offers parts treated with PF85 (sp?) so no oil is ever needed and it fouls less.
number one rule; you get what you pay for.
number two rule; a bird in the hand is better than none at all, having spare parts are signs of smart person, especially in a weapon with many moving parts, so forget the fancy toys and get the spare parts .