Those Dells would be better than Mac Minis for a lot of things, but not others. Clearly the Dell is more expandable and potentially more powerful depending on

Those Dells would be better than Mac Minis for a lot of things, but not others. Clearly the Dell is more expandable and potentially more powerful depending on config. 32GB RAM ceiling is fantastic too, especially for virtualization. Physical size is an issue for some applications but not others. Either one of these would be fine as a workstation, but I know which one of these boxes I'd want in my living room. Size also matters if you're racking these things up, or having one colo'd somewhere. The Mac Mini kills the Dell in terms of performance/watt, especially when you move past the base CPU models of either the Mini or the T20. That alone can erase the price advantage of the Dell (over several years of ownership) if you're using them as always-on servers and you factor in the cost of providing cooling for them as well. Again, this is an issue in some scenarios but not others.