Re: Cost is the smaller concern
> someone else's hacked and undocumented spaghetti code
Don't forget that with closed-source software, this is also often exactly what you're getting - only you can't do anything about it, and you might not even be aware of just how hacked and spaghettified it really is.
> will they charge you less than a commercial supplier would?
That marvellous thing, the invisible hand of the market, comes into play at this point. A closed-source product creates a monopoly on service for its copyright holder. Open-source software can by maintained by anyone - you are free to select a supplier and discriminate on price, quality, confidence in their ability, etc. Competition can actually apply to this market, where with a closed product your options are limited to a) what the supplier wants to charge b) an expensive change to a competitor's product.