This article provides some excellent advice to linux software vendors, citing examples of the issues caused by the all-too-common carelessness of the companies. I have to highlight this and point out that they're right on all counts.

I also want to say that I think Best Practical, makers of RT, very much have the right idea when they provide an open source product, that works and can be used out of the box by any competent sysadmin. But they provide a level of service above and beyond. Their technical support and consulting costs some money -- and is worth every penny -- and as consultants they will happily set up your RT system as customized as you could ever desire.