I had one. Don't remember the brand. Seemed like hours to get my Skil drill aligned. Worked OK if I had one hand to hold the work, one hand to make the plunge action and another hand to turn the drill on/off (you doing the math here?) If I ever wanted to use my drill again for any other purpose, I had to repeat the entire alignment process.
So, I gave it to a photog who wanted a simple camera copy stand. We're both happy.
Delta had cute little 8" bench-top drill presses on for $100 (reg $150). Fantastically useful. I still dream of the day that I have the $$$ and space for a floor stand DP. In the meantime, I'm 98% satisfied.