In my mind there is little doubt that open source software really makes the most sense for learning. Learning is messy and one size does not fit everyone. Whether you approach it from a socio-constructivist perspective, as a behaviourist or only focus on the anticipated return on investment, there is no one correct way to support learning.
This means that whatever path you take, it will not be the best for everyone at all times. I suggest that you hedge your bets and invest in people instead of technology. Open source software lets you do this. Whether the case be for training or education, your major investment should NOT be in your technology. You would be better served if you cobbled together some free, open source learning applications and then invested in people to deal with the core performance issues. This "how to" support would be worth more than any fancy graphical user interface within a corporate learning portal.
For instance, I recently came across some figures for the cost of portals. Costs for proprietary systems ranged from $10,000 per processor to $125,000 per server. Using free, open source software, you could easily hire two full-time workers people for the cost of the more expensive system. Perhaps one person to handle the technical issues and the other to focus on the learning processes. In this way you would have money to spare as well as a more flexible operating model. There may be cases where you will need to purchase software but this only should be in order to meet a particular requirement that is critical for your organisation. It could be a specific online conferencing utility or perhaps a scheduling system suited to your industry. Just remember to check out the open source options first.
In the learning business, if an application meets 80% of your "wish list" requirements, then it will probably do the job in the long run. In most cases there is a suitable open source application that can address your needs. Therefore, don’t waste the bulk of your budget on your technology platform but invest it in good tools, instructors, processes, peer support groups or anything else that will benefit the learners every day. There is too much shelfware [applications that sit on the shelf and gather dust] out there to really believe that any technology will address all of your learning needs. It’s about the people …