Not a dilemma. It depends on what one wants - like everything else. The dilemma is perceived since so many computer users are weaned on proprietary software, and the rebels decry anything but free software. Open-source doesn't necessarily mean free, only that the source is available.

As for utility; If an open-source (preferably free) solution is available that reliably suits my needs or those of a client that is the one I'll recommend. If the only way to solve the problem or get the job done is with a proprietary solution, well, then that is obviously the way to go (at least till a comparable or better open-source solution appears).